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Willis Tower

May 02, 2023

The Willis Tower (originally the Sears Tower) is a 110-story, 1,451-foot (442.3 m) skyscraper in the Loop community area of Chicago in Illinois, United States. Designed by architect Bruce Graham and engineer Fazlur Rahman Khan of Skidmore, Owings & Merrill (SOM), it opened in 1973 as the world's tallest building, a title that it held for nearly 25 years. It is the third-tallest building in the Western Hemisphere, as well as the 23rd-tallest in the world. Each year, more than 1.7 million people visit the Skydeck observation deck, the highest in the United States, making it one of Chicago's most popular tourist destinations.[4]

Willis Tower
Former namesSears Tower (1973–2009)
Record height
Tallest in the world from 1973 to 1998[I]
Preceded byWorld Trade Center
Surpassed byPetronas Towers
General information
StatusCompleted
TypeOffice, observation, communication
Architectural styleInternational
Location233 S. Wacker Drive
Chicago, Illinois 60606
United States
Coordinates41°52′44″N 87°38′09″W / 41.8789°N 87.6358°W / 41.8789; -87.6358Coordinates: 41°52′44″N 87°38′09″W / 41.8789°N 87.6358°W / 41.8789; -87.6358
Current tenantsUnited Airlines
Named forWillis Towers Watson
Sears (1973–2009)
Construction started1970; 53 years ago (1970)
Completed1974; 49 years ago (1974)
OpeningSeptember 1973; 49 years ago (September 1973)
OwnerBlackstone Group[2]
Height
Architectural1,451 ft (442 m)[1]
Tip1,729 ft (527 m)[1]
Top floor1,354 ft (413 m)[1]
Technical details
Floor count108 (+3 basement floors)[3]
Floor area4,477,800 sq ft (416,000 m2)[1]
Lifts/elevators104,[1] with 16 double-decker elevators, made by Westinghouse, modernized by Schindler Group and recently remodernized by Otis Elevator Company
Design and construction
Architect(s)Skidmore, Owings & Merrill[1]
Fazlur Rahman Khan
Bruce Graham
EngineerJaros, Baum & Bolles (MEP), Aon Fire Protection Engineering, formerly Schirmer Engineering Corporation (Fire)[1]
Structural engineerSkidmore, Owings & Merrill
Main contractorMorse Diesel International
References
I. ^ . Emporis. Archived from the original on September 23, 2015.
[1]

The building occupies a site bounded by Franklin Street, Jackson Boulevard, Wacker Drive, and Adams Street. Graham and Khan designed the building as nine square "tubes", clustered in a 3×3 matrix; seven of the tubes set back at upper floors. The tower has 108 stories as counted by standard methods, though the building's owners count the main roof as 109 and the mechanical penthouse roof as 110.[1][3] The facade is made of anodized aluminum and black glass. The base of the building contains a retail complex known as the Catalog. The lower half of the tower was originally occupied by retail company Sears, which had its headquarters there until 1994, while the upper stories were rented out.

The structure was known as the Sears Tower from its construction until the naming rights were included in a 2009 lease with the Willis Group. Local area residents still refer to the building by its old name.[5] As of April 2018, the building's largest tenant is United Airlines, which occupies around 20 floors.[6][7][8] Other major tenants include the building's namesake Willis Towers Watson and law firms Schiff Hardin and Seyfarth Shaw.[8] Morgan Stanley became the building's fourth-largest tenant in 2017.[8][9]

History

Planning

Site selection

Sears, Roebuck & Co. had occupied an office complex on Chicago's west side since 1906. The existing offices were inadequate by 1966, prompting Sears executives to begin searching for a new site.[10] By 1969, Sears was the largest retailer in the world, with about 350,000 employees.[11] Sears executives quickly determined that a new headquarters complex in the suburbs was infeasible, since it would require relocating about 7,000 employees. Instead, Sears executives decided to consolidate the thousands of employees in offices distributed throughout the Chicago area into one building on the western edge of Chicago's Loop.[10][12]

Sears asked its outside counsel, Arnstein, Gluck, Weitzenfeld & Minow (now known as Arnstein & Lehr, LLP) to suggest a location. The firm consulted with local and federal authorities and the applicable law, then offered Sears two options.[13] The first option was the Goose Island area northwest of the Loop, but Sears's vice president of real estate, Matthew J. Stacom, rejected this proposal. The other was a two-block area in the Loop, bounded by Franklin Street on the east, Jackson Boulevard on the south, Wacker Drive on the west, and Adams Street on the north. Though the site was more centrally located, it was also relatively small, with about 55,000 square feet (5,100 m2). Bernard Feinberg, Albert I. Rubenstein, and Philip Teinowitz had assembled that site over the previous five years, but they had failed to acquire a neighboring 74,000-square-foot (6,900 m2) lot from bus company Greyhound Lines.[14]

Feinberg, Rubenstein, and Teinowitz then bought options for three adjacent lots. Under the terms of each option, unless the three men were able to acquire at least one of the lots within 90 days, all three options would be forfeited.[14] Ultimately, Sears acquired the Loop site in 1970.[14][15] Sears then obtained permits to close down one block of Quincy Street, which bisected the site from east to west. Attorneys from the Arnstein firm, headed by Andrew Adsit, began buying the properties parcel by parcel.[16] Sears purchased 15 buildings from 100 owners and paid the government of Chicago $2.7 million for the block of Quincy Street that was to be closed down.[15]

Design process

Sears executives estimated that their new building would need about 4.2 million square feet (390,000 m2), split into 70 stories with 60,000 square feet (5,600 m2) each or 60 stories with 70,000 square feet (6,500 m2) each.[10] Sears commissioned architecture firm Skidmore, Owings & Merrill (SOM) to design the tower.[17] SOM was also the lead structural engineer, and Jaros, Baum & Bolles provided MEP engineering.[1]

Sears planned to move its merchandise group into the building initially, renting out the remaining space to other tenants until needed. Sears executives were accustomed to large floor areas of at least 100,000 square feet (9,300 m2), but SOM architects raised concerns that the large floors would be unattractive to smaller tenants. A subsequent proposal called for two buildings connected by a footbridge, which would respectively contain 50,000 square feet (4,600 m2) and 30,000 square feet (2,800 m2) on each floor, but this was also infeasible.[17]

Some floors were designed with smaller footprints to attract prospective lessees, so the building's height was increased to meet Sears's floor-area requirements.[17] Architect Bruce Graham and structural engineer Fazlur Rahman Khan, both of whom were partners with SOM, proposed a tower with 55,000-square-foot (5,100 m2) floors in the lower part of the building, as well as a series of setbacks with gradually tapering floor plates, giving the tower its distinctive look.[18] During the design process, one of the architects reportedly pulled out nine cigars and staggered them vertically until the pair both agreed to the arrangement.[18][19] This allowed Sears to occupy the large lower stories, while providing more conventional office space that could be rented out on the upper stories.[20] The firm of Saphier, Lerner, Schindler was responsible for determining Sears's space requirements and designing furniture for the company.[14][21] It conducted a year-long study to determine how 16 of the company's departments should be laid out within the building.[21]

As Sears continued to offer optimistic growth projections, the height of the proposed tower also increased.[17] Under Chicago's relatively lax zoning laws, the site could theoretically accommodate a 300-story building with 13.5 million square feet (1,250,000 m2).[14] In practice, most potential tenants did not want excessively high offices.[14] Additionally, the Federal Aviation Administration (FAA) restricted the height of structures in the area to protect air traffic.[14][17] FAA officials publicly denied that they had imposed a height limit;[22] however, the area's minimum safe altitude would need to be raised by 1,000 feet (300 m) if the building was just 1 foot (0.30 m) taller.[23] Plans for the tower were announced on July 27, 1970. The 1,450-foot-tall (440 m) building would contain 109 stories as measured from Wacker Drive and 110 stories as measured from Franklin Street.[15][24] This would make Sears's new tower the tallest in the world, as measured by roof height, although New York City's under-construction World Trade Center Twin Towers would have a taller antenna.[22] Although the Sears Tower would contain 4.4 million square feet (410,000 m2) of space, only about 3.7 million square feet (340,000 m2) would be used as offices.[24]

Construction

Early construction

 
The Sears Tower (now Willis Tower) during its construction in 1973

Work on the building's foundation commenced in August 1970. Contractors excavated the lot to a depth of 50 feet (15 m), and they removed 180,000 cubic feet (5,100 m3) of dirt from the site.[25] By that November, Spencer, White & Prentis Inc. was excavating a trench around the site, measuring 60 feet (18 m) deep and 20 by 216 feet (6.1 by 65.8 m) across. The contractors then built a slurry wall within the trench, made of concrete and reinforced steel.[26] Workers used steel bracing to prevent the slurry wall from collapsing inward, then used caissons to drill 201 holes into the ground. They also rerouted a sewer that had run underneath Quincy Street, which was to be closed permanent as part of the tower's construction.[25]

The Diesel Construction Company was hired as the Sears Tower's general contractor.[27] Sears, Roebuck & Co. chairman Gordon M. Metcalf installed the building's first steel beam at a ceremony on June 7, 1971.[28][29] The project employed 2,000 workers. To accelerate the building's construction, a concrete plant was built in the building's basement, allowing workers to pour one-third of a concrete floor every day. Contractors built two temporary kitchens on the site for workers, and telephone and loudspeaker systems were installed on every floor to allow workers to communicate. In addition, contractors installed temporary generators that could supply up to 14,000 kilowatts (19,000 hp) simultaneously; during the winter, most of this electricity was used to heat the exposed steel beams on the lowest five floors.[30]

Broadcast-signal controversy

By late 1971, Chicagoland residents and broadcasters had raised concerns that the new Sears Tower would disrupt television broadcasts.[31][32] According to one estimate, the building would obstruct television signals for 15 percent of Chicagoans and cause "double images" for another 20 percent,[31] primarily affecting communities to the northwest and southeast.[32] The same year, officials of the village of Skokie, northwest of Chicago, threatened to request an injunction to prevent further construction.[33][34] In response to these concerns, Sears started researching methods to reduce the tower's effect on broadcast signals. Variety magazine stated that the Sears Tower did not interfere with broadcasts on its own, since several shorter towers in the Loop also interfered with broadcast signals.[35] Nonetheless, the Illinois Citizens' Committee for Broadcasting filed a formal complaint with the Federal Communications Commission (FCC) in February 1972.[36][37]

The first lawsuit against the building was filed by the state attorney in neighboring Lake County on March 17, 1972.[38][39] A second suit was filed on March 28 in Cook County Circuit Court by the villages of Skokie, Northbrook, and Deerfield, Illinois.[39][40] Sears filed motions to dismiss the Lake and Cook County lawsuits, which both sought to cap the building at 67 stories.[40] Sears studied the possibility of erecting antennas atop its tower in April 1972,[41] and the tower's construction continued, even as decisions on both lawsuits were delayed.[42] At the end of the month, the company applied for permission to increase the building's height limit by 350 feet (110 m) and install a new antenna,[43][44] although eight of Chicago's ten television stations criticized the plan.[45][46] On May 17, 1972, Judge LaVerne Dickson, Chief of the Lake County Circuit Court, dismissed the suit, saying, "I find nothing that gives television viewers the right to reception without interference."[47] By then, the building had reached the 58th story.[48] The Lake County attorney appealed to the Illinois Supreme Court.[48] In his decision on June 12, Judge Charles R. Barrett contended the plaintiffs did not have a right to undistorted television reception.[49]

Meanwhile, the FCC declined to act on the height dispute on the grounds it did not have jurisdiction.[50] The FAA approved the antennas atop the tower in June 1972,[51][52] and the Illinois Supreme Court affirmed the previous rulings by Lake and Cook County circuit courts at the end of the month.[53] Work was temporarily paused that July due to a labor strike.[54] The next month, Sears formally announced plans for broadcast antennas on the tower's roof,[55][56] and the company offered to spend $5 million to help relocate broadcast stations to the Sears Tower.[55] The United States Court of Appeals for the Seventh Circuit upheld the FCC's decision in September,[57] and the United States Supreme Court refused to hear an appeal of the Seventh Circuit's decision that November.[58][59]

Topping-out and completion

In November 1972, the Sears Tower became Chicago's tallest building,[60] surpassing the Standard Oil Building, which had held the record for one month.[61] At the time, the Sears project employed 1,600 workers in three shifts; one worker had been killed during the project so far.[27][60] The building's final completion had been delayed significantly due to labor strikes and bad weather. The concrete work had reached the 77th floor, while the steel superstructure had reached the 84th floor; the remainder of the steelwork would be difficult to construct because of high winds at higher altitudes.[60] Local television stations WTTW and WLS-TV were planning to install temporary broadcast antennas atop the tower when the steel frame was completed.[62] The tower's superstructure had reached the 100th floor in February 1973, at which point it was taller than the Empire State Building in New York City.[63]

The building was topped out on May 3, 1973.[64] The day before the event, the Chicago Tribune's editorial board wrote: "Move aside, New York. After tomorrow, when schoolchildren dream of big buildings, they'll no longer think of you and the Empire State Building and the World Trade Center."[65] The frame was still not technically complete, as three to four stories remained to be built.[66] One week after the ceremony, four workers died after an elevator shaft caught fire.[66][67] A fifth worker died after falling from the tower in an unrelated incident four days later.[68] Work was halted again that June due to a labor strike,[69][70] and Sears began moving furniture into the building that month.[71] The construction cost was about US$150 million,[72] equivalent to $920 million in 2021 dollars.[73] Despite the size of the project, Sears executives said the building could not accommodate Sears' annual shareholder meetings, and the company continued to rent space in other structures.[74]

20th century

Opening and early years

The first Sears employees began moving into the tower during the weekend of September 9, 1973.[71][75] Flashing beacons on the building's roof, the first to be installed at any building in Chicago, were activated the same month.[76] Upon the tower's opening, broadcasters at the John Hancock Center, Chicago's second-tallest building, had to decide whether to relocate to the Sears Tower.[77] Two television stations decided to relocate.[78] Six other stations remained at the John Hancock Center, citing a study which showed that relocating to the Sears Tower would provide only minimal benefits.[78][79] Documents released in late 1973 indicated that the Sears Tower would cause much more interference than either Sears or the television stations had disclosed.[79] WLS-TV moved to the Sears Tower in February 1974,[80] followed by WTTW the next month.[81]

By March 1974, three-fourths of the space in the building was occupied; Sears had leased the upper stories to tenants such as Goldman Sachs, Northwest Industries, and Schiff Hardin.[82] A mobile sculpture by Alexander Calder was dedicated in the lobby in October 1974.[83][84] Sears' optimistic growth projections were not realized; instead, in late 1974, the company fired 500 workers, about seven percent of the 7,000 Sears employees that worked in the tower.[85] Competition beyond its traditional rivals such as Montgomery Ward arose from emerging retail giants including Kmart, Kohl's, and Walmart. As a result of a surplus of office space that emerged in the 1980s, the tower did not draw as many tenants as projected and so stood half-vacant for a decade.

Renovation and relocation

 
The tower in 1978, after its completion

In February 1984, Sears announced that it would renovate the building to attract visitors to the lower floors.[86][87] At the time, 6,500 Sears employees occupied more than half of the building,[87][88] taking up the lowest 48 stories.[88] The remainder of the tower was occupied by 5,500 employees from about 70 companies.[87] As part of the project, the main entrance was covered with a four-story glass dome, and the first four stories were converted into a shopping atrium. In addition, a visitor center for the building's Skydeck was constructed.[86][87] The renovations, designed by SOM, were completed in mid-1985.[88] Paul Gapp of the Chicago Tribune wrote that SOM had "scaled the new entrance skillfully, in keeping with the main building's height" and that the new atrium "relieves the formerly cramped feeling from just inside the Franklin entrance".[89]

Sears announced in 1988 that it would sell the tower and relocate its merchandising division from the lower half of the building.[90] The company wanted to earn at least $1 billion from the sale of the Sears Tower, so it offered multiple concessions to potential buyers, including a guarantee that Sears would continue to pay rent on the lower half of the building until tenants were found for these stories.[91] Four large firms were negotiating to buy the tower by July 1989.[92] The company had difficulties finding a buyer, in part because the lower stories were too large for many potential tenants.[93] Sears nearly sold the tower to Canadian company Olympia & York, but the deal was canceled in September 1989 because the two firms could not agree on who would pay the property taxes.[94] In November 1989, Sears decided to instead refinance the building.[95] The next year, Sears took out a mortgage loan on the tower for $850 million from MetLife and AEW Capital Management, with MetLife as the holder of the mortgage note; the loan would mature in 2005.[96]

In 1990, the law firm of Keck, Mahin & Cate decided to move into a development that would become 77 West Wacker Drive, rebuffing Sears' attempts to entice the firm to stay.[97] Just two years later, Sears began moving its own offices out of the building[98] to a new campus in Hoffman Estates, Illinois, which was completed in 1995.[96] As the maturation of the mortgage approached, Sears renegotiated the loan in 1994. The negotiations resulted in an agreement where Sears would no longer be liable for the $850 million loan, although it would only nominally own the building, while AEW and MetLife effectively had total control. As part of the 1994 agreement, AEW and MetLife would be able to take official ownership of the building in 2003.[96] In 1997, Toronto-based TrizecHahn, at the time the lessee of the CN Tower, acquired AEW's holdings in the building for $110 million, assuming $4 million in liabilities and a $734 million mortgage.[99][100]

21st century

Trizec had projected that the Sears Tower would quickly reach a value of $1 billion. These projections were not met, with the tower facing the same vacancy and other problems it saw under Sears, although Trizec made somewhat successful efforts to attract new tenants. Following the September 11 attacks, two of the largest tenants, Goldman Sachs and Merrill Lynch, immediately announced plans for vacating 300,000 ft2 of space. In 2003, Trizec sold its holdings of the tower to MetLife for $9 million.[101]

Syndicate ownership

In March 2004, MetLife announced that it would sell the building to a group of investors,[102][103] including Joseph Chetrit, Joseph Moinian, Lloyd Goldman, Joseph Cayre, and Jeffrey Feil of New York, as well as American Landmark Properties of Skokie, Illinois.[104] The quoted price was $840 million, with $825 million held in a mortgage.[105] Two years later, in February 2007, the Sears Tower's owners obtained a $780 million loan from UBS.[106] At the time, UBS valued the tower at $1.2 billion.[107]

 
The tower at night in 2009

Since 2007, the owners had considered plans for the construction of a hotel on the north side of Jackson Boulevard, between Wacker Drive and Franklin Street, close to the entrance of the observation deck, above the tower's underground parking garage. According to the tower's owners, the second building was considered in the original design. The plan was eventually cancelled as city zoning did not permit construction of such a tall building in that location.[108] In February 2009, the owners announced they were considering a plan to paint the structure silver, an idea that was later abandoned. It was hoped that a new, silver, paint-job would "rebrand" the building and highlight its advances in energy efficiency for an estimated cost of $50 million.[109]

Although Sears' naming rights expired in 2003, the building continued to be called the Sears Tower for several years, despite multiple changes in ownership. In March 2009, London-based insurance broker Willis Group Holdings agreed to lease a portion of the building and obtained the naming rights.[110][111] On July 16, 2009, the building was officially renamed the Willis Tower.[112][113] By 2011, the building's owners were considering selling a partial ownership stake, or even the entire building, to an investor.[114] The next year, United Airlines announced it would move its corporate headquarters from 77 West Wacker Drive to Willis Tower.[6]

Blackstone ownership

By March 2015, the Willis Tower was being marketed at a price of $1.5 billion.[115] The same month, the Blackstone Group purchased the tower for a reported $1.3 billion, the highest price ever paid for a property in the U.S. outside of New York City.[116][117] Blackstone announced a $500 million renovation in January 2017, which would include the construction of the Catalog, a six-story commercial complex, replacing a plaza on Jackson Boulevard and the entrance on Wacker Drive.[118][119] Architectural firm Gensler designed the renovation.[120][121] A rooftop terrace was built atop the Catalog, and the building's HVAC systems were overhauled.[120] Most of the building's elevators, excluding those that served the Skydeck, were also renovated for the first time in the tower's history. The new elevators would be faster than the original elevators and would use use 35 percent less energy.[122][123] The building's owners installed artwork by Olafur Eliasson, Jacob Hashimoto, and other artists.[120]

To fund these improvements, in February 2017, Blackstone obtained a $1 billion loan from a group of banks including Goldman Sachs. The new loan replaced $750 million of CMBS debt that was maturing.[124] The following year, because of the increasing costs of the renovation,[125] Blackstone received a new $1.3 billion loan from Deutsche Bank and Barclays.[126][127] The Wacker Drive entrance was demolished in early 2018 to make way for the Catalog.[128] A steel globe next to the entrance, manufactured by the Poblocki Sign Company and installed in 2010, was relocated to Elmhurst, Illinois.[128][129] A 40,000-square-foot (3,700 m2) private club on the 66th and 67th stories opened in June 2018. The club included a restaurant named Craftsman and a lounge named Frame, both of which exclusively served the tower's tenants, as well as a public restaurant known as the East Room.[130][131] That September, Urbanspace announced that it would operate a food hall on the lower stories.[132][133]

In 2020, insurance company Aon had proposed acquiring Willis Towers Watson (which had succeeded the Willis Group as the building's owner),[134][135] prompting speculation that the building could be renamed again.[136] The planned merger was canceled in 2021 following an antitrust lawsuit from the United States Department of Justice.[137] The building's renovation was completed in May 2022.[120][138][139] At the time, although the Willis Tower was nearly 85 percent leased, the number of tenants and visitors entering the building had decreased significantly since 2019, in part because of the COVID-19 pandemic in Chicago.[120] In April 2023, the New York Times reported that Blackstone had written down the value of its investment in the tower by $119 million.[140]

Incidents

In June 2006, seven men were arrested by the FBI and charged with plotting to destroy the tower. Deputy FBI Director John Pistole described their plot as "more aspirational than operational".[141][142] The case went to court in October 2007.[143] After three trials, five of the suspects were convicted and two acquitted.[144] The alleged leader of the group, Narseal Batiste, was sentenced to 13+1⁄2 years in prison.[145] In response to the perceived threat of an attack, the building's largest tenant at this time, Ernst & Young, moved to North Wacker Drive in early 2009.[146]

In May 2020, heavy rains caused three of the basement levels to flood, knocking out power to the building. This also resulted in many TV and radio stations going off the air.[147]

Architecture

 
Breakdown of the bundled tube structure of Willis Tower with simplified floor plans

The Willis Tower was designed by architect Bruce Graham and structural engineer Fazlur Rahman Khan of Skidmore, Owings and Merrill.[148] Graham and Khan designed the building as nine square "tubes", clustered in a 3×3 matrix forming a square base with 225-foot (69 m) sides.[17][18] The building's total area is 3,787,200 sq ft (351,800 m2).[149] The structure was intended to accommodate 16,500 employees.[150]

Form and facade

Each of the "tubes" is a column-free module measuring 75 by 75 feet (23 by 23 m),[151] which set back at different stories.[19] There are setbacks at the 50th, 66th, and 90th floors.[84][152][12] The lowest 50 stories contain nine tubes and cover 52,000 square feet (4,800 m2) each.[17][18][20] The northwest and southeast tubes terminate at the 50th floor. The 51st through 66th floors each span 41,420 square feet (3,848 m2), above which the northeast and southwest tubes end. From the 67th to 90th floors, each story is shaped like a cross, covering 30,170 square feet (2,803 m2). The north, east, and south tubes end at the 90th floor; the remaining west and center tubes reach 108 floors, with an area of 12,283 square feet (1,141.1 m2) on each of the top stories.[17]

 
Sculpture honoring Fazlur Rahman Khan, considered the father of tubular designs, at the Willis Tower. Khan is known for making important advancements in skyscraper engineering.

The Sears Tower was the first building to use this innovative design. It was both structurally efficient and economic: at 1,450 feet, it provided more space and rose higher than the Empire State Building and cost much less per unit area.[153] The system would prove highly influential in skyscraper construction and has been used in most supertall buildings since, including the world's current tallest building, the Burj Khalifa.[154][155] In February 1982, two television antennas were added to the structure, increasing its total height to 1,707 feet (520.3 m). The western antenna was later extended, bringing the overall height to 1,729 feet (527 m)[1] on June 5, 2000, to improve reception of local NBC station WMAQ-TV.

The perimeter of the Willis Tower contains columns that are spaced 15 feet (4.6 m) apart on their centers. The facade is made of anodized aluminum and black glass.[84][152] Alcoa manufactured 4 million pounds (1.8 kt) of aluminum sheeting for the building's facade.[156] Black bands appear on the tower around the 29th–32nd, 64th–65th, 88th–89th, and 104th–108th floors. These elements are louvers to ventilate the building's environmental support systems and obscure its belted trusses.[157] The rest of the facade is made of 16,000 rectangular windows.[158][159] all of which measure 5 by 8 feet (1.5 by 2.4 m) and are tinted with bronze.[159]

Outside the building, there was originally a 80,000-square-foot (7,400 m2) plaza made of pink granite.[158] In the late 2010s, a three-level wing was built along the western and southern sides of the tower replacing the tower. The roof garden above the annex spans 30,000 square feet (2,800 m2).[121][160] The annex contains a facade of black steel and aluminum, similar to in the original building.[121] The Jackson Boulevard facade of the annex contains an artwork by Olafur Eliasson, entitled Atmospheric wave wall.[161][162] The work, measuring 30 by 60 feet (9.1 by 18.3 m) across,[161] comprises almost 2,000 blue-and-green steel tiles, which are decorated with hexagonal motifs.[162][163] The wall is backlit at night.[161][162]

Structural and mechanical features

The interior includes 74,000 short tons (66,000 long tons; 67,000 t) of steel, 4 million pounds (1.8 kt) of aluminum, and 101 acres (4,400,000 sq ft; 410,000 m2) of concrete flooring.[159][27] The building contains diagonal columns only on the two stories immediately below each of the setbacks, thus reducing shear stress.[152] The interior of the building could not contain diagonal beams, since these would have obstructed the connections between each of the "tubes". Therefore, the columns and the horizontal beams on each story are connected by rigid joints.[84] The superstructure was designed to withstand wind gusts of 130 miles per hour (210 km/h), which on average would occur once every hundred years.[150] According to the Chicago Tribune, the top of the building would be able to bend by as much as 7 inches (180 mm), returning to its normal position within 7.2 seconds.[158]

The Willis Tower's basement extends 50 feet (15 m) deep, resting on a 5-foot-thick (1.5 m) concrete slab. The ground directly beneath the building was largely made of clay; the underlying layer of limestone was as much as 100 feet (30 m) beneath ground level.[25] As a result, the foundation was excavated using 201 caissons,[25][23] of which 114 reached the underlying limestone.[23] The caissons created holes that measured up to 10 feet (3.0 m) across. Some holes at the northwestern and northeastern corners of the site filled up with groundwater and had to be drained. Workers next placed steel tubes into the holes, then poured concrete around the tubes.[25]

During the Sears Tower's construction, SOM and Chicago government officials considered adding "smoke free and fire free" areas to the building, as well as a complete sprinkler system serving all floors. Neither of these features had previously been used in a structure in Chicago.[164] Even though regulations did not require a fire sprinkler system, the building was equipped with one from the beginning. There are around 40,000 sprinkler heads in the building, installed at a cost of $4 million.[157] When it was completed, the Sears Tower was heated electrically, unlike older structures that used gas heating.[165] It included 145,000 light fixtures and a cooling system capable of 17,000 tons of refrigeration.[27][12] Furthermore, the tower contained fire-suppression and communications systems for emergency use, which were powered by diesel generators.[150][166] If there was a fire in one section of the building, the building's smoke-detection system would close off the fresh-air intake openings in that section, discharging smoke outdoors.[150]

Fifteen above-ground stories, as well as three of the basement levels, contain mechanical equipment. Above the Skydeck on the 103rd floor is a seven-story mechanical penthouse.[12]

Elevators and escalators

The Sears Tower was planned with 103 elevators,[150][158] including 14 double-deck elevators.[150][167] The office stories are served by 97 elevator cabs; due to the presence of the double-deck elevators, these occupy 83 shafts.[123] As designed, one bank of single-deck elevators connected the lobby to the lowest 28 stories.[167] Banks of double-deck elevators traveled to "sky lobbies" at the 33rd/34th and 66th/67th floors, where passengers could transfer to local elevators. The 34th through 103rd stories were served by local elevators that operated from the sky lobbies.[150][167] Two elevators also ran directly from the lobby to the Skydeck on the 103rd floor.[168] As of 2018, the elevators carried 5.8 million passengers per year.[122][123]

Six of the elevators are used for freight.[158] One of the freight elevators served all stories, traveling to a height of 1,440 feet (440 m).[168] During a fire or another emergency, this elevator would be reserved for the Chicago Fire Department. Other elevators would be controlled from the 33rd floor. During a fire, elevators would be dispatched to the affected floors to assist with evacuation.[150]

The building also had 16 escalators, including a set of double-height escalators that traveled from the main lobby to the lower mezzanine.[167] Another set of escalators connects the 33rd and 34th stories.[158]

Interior

Base

 
Bottom of the tower

When the building was completed, the main entrance was on Wacker Drive to the west. There was a plaza on the south side of the building, sloping upward toward Franklin Street to the east. The Franklin Street side of the building was 6 feet (1.8 m) lower than the Wacker Drive entrance, so the entrances on Franklin Street were actually below the plaza, leading to the building's lower mezzanine.[167] Below ground level are three basement levels with a total area of 400,000 square feet (37,000 m2).[14] The basements included a 1,200-seat cafeteria, commercial space, service areas, and a loading dock for 17 trucks.[84] The basement also contained a 150-spot parking garage.[158]

As of 2022, the building's base covers 463,000 square feet (43,000 m2) and contains two lobbies for tenants.[120][121] The building's tenants primarily enter from Wacker Drive and Franklin Street. Shoppers, restaurant patrons, and visitors to the Skydeck observation deck use the southern entrance on Jackson Boulevard.[160] The Wacker Drive lobby contains In the Heart of this Infinite Particle of Galactic Dust, a 2019 artwork by Jacob Hashimoto. It consists of over 7,000 rice-paper and resin disks that are hung from the ceiling.[161][169] To honor Khan's contributions to skyscraper engineering design, the Structural Engineers Association of Illinois also commissioned a sculpture of him for the lobby of the Willis Tower.[170]

The commercial complex at the building's lowest stories is known as the Catalog, a reference to Sears' mail-order catalogs.[121][171] The six-story complex includes numerous restaurants.[171] It extends into three of the building's basement levels, as well as the three-story annex to the south and west of the tower.[121] The roof of the annex includes a curved skylight with 240 glass panes, and the northern section of the annex's roof is supported by black columns that resemble those in the original tower. The Catalog also contains decorative details, such as handrails and staircase landings, which are inspired by elements of Chicago's "built environment".[172] The third story of the Catalog contains a 30,000-square-foot coworking space operated by Convene.[160][172]

Skydeck

 
Four glass-bottom skyboxes on the west facade of Willis Tower at the 103rd floor
 
Glass balcony at the Skydeck

The Willis Tower observation deck, called the Skydeck, opened on June 22, 1974. Located on the 103rd floor, 1,353 feet (412.4 m) above ground level, it is the highest observation deck in the United States[173] and one of Chicago's most famous tourist attractions.[174] Tourists can experience how the building sways in wind and see far over the plains of Illinois and across Lake Michigan to Indiana, Michigan, and Wisconsin in clear conditions. Elevators reach the top in about 60 seconds, allowing occupants to feel the change in pressure as they ascend. The Skydeck competes with the John Hancock Center's observation floor a mile and a half away but reaching 323 feet (98.5 m) lower. Some 1.7 million tourists visit annually. A second observation deck on the 99th floor serves as a backup.

In January 2009, a major renovation of the Skydeck began, including the installation of retractable glass balconies which extend approximately 4 feet (1.2 m) from the facade of the 103rd floor, overlooking South Wacker Drive. The all-glass boxes, informally dubbed "The Ledge", allow visitors to see the street below. The boxes, which can accommodate 5 short tons (4.5 metric tons), opened to the public on July 2, 2009.[175][176] On May 29, 2014, the laminated glass flooring of one of the boxes cracked while visitors were inside, but there were no injuries.[177] The flooring of the same box cracked again on June 12, 2019.[178] In May 2022 a fifth glass ledge opened on the west facade overlooking South Wacker Drive.

 
Panorama of Chicago skyline as seen from Willis Tower Skydeck

Height

 
Height comparison with (left to right) Burj Khalifa, Dubai; CN Tower, Toronto; Willis Tower, Chicago

When completed, the Sears Tower was the world's tallest building but not the world's tallest structure. Toronto's CN Tower was about 350 feet (106.7 m) taller,[179] although the Council on Tall Buildings and Urban Habitat (CTBUH) does not consider the CN Tower to be a building, since it does not have floors from the ground up.[180] The Willis Tower remains the third tallest building in the Americas and in the Western Hemisphere (after One World Trade Center and Central Park Tower in New York City). With a pinnacle height of 1,729 feet (527 m), it is the third-tallest freestanding structure in the Americas.[1] It is the 16th-tallest freestanding structure in the world by pinnacle height.

When the Petronas Twin Towers in Kuala Lumpur, Malaysia, was completed in 1998, it claimed to be the tallest building in the world, measuring 1,482.6 feet (451.9 m) tall including decorative spires. Chicagoans objected to this claim on the basis that the Sears Tower's top floor was higher than that of either of the Petronas Towers.[181] In the ensuing controversy, four categories of "tallest building" were created. Of these, Petronas was the tallest in the category of height to the top of architectural elements, meaning spires but not antennas.[181][182] Taipei 101 in Taiwan claimed the record in three of the four categories in 2004, surpassing the Petronas Twin Towers in spire height and the Sears Tower in roof height and highest occupied floor. People suggested that Sears add cosmetics atop its tower to surpass Taipei 101, but this did not materialize.[183][184] On August 12, 2007, the Burj Khalifa in Dubai was reported by its developers to have surpassed the tower in all height categories.[185] Upon completion, One World Trade Center in New York City surpassed the Willis Tower through its structural and pinnacle heights, but not by roof, observation deck elevation, or highest occupied floor.[186]

Until 2000, the tower did not hold the record for being the tallest building by pinnacle height. From 1969 to 1978, this record was held by John Hancock Center, whose antenna reached a height of 1,500 feet (457.2 m), 49 feet (14.9 m) taller than the Sears Tower's original height. One World Trade Center became taller by pinnacle height with the addition of a 359-foot (109.4-meter) antenna, bringing its total height to 1,727 feet (526.4 m). In 1982, two antennas were installed which brought its total height to 1,707 feet (520.3 m), making it taller than the John Hancock Center but not One World Trade Center. However, the extension of the tower's western antenna in June 2000 to 1,729 feet (527 m) allowed it to just barely claim the title of tallest building by pinnacle height.

The lowest level of Willis Tower is 43 feet (13 m) below the elevation of Franklin Street.[187]

Climbing

 
View of the wall of the tower from the Skydeck

On May 25, 1981, Dan Goodwin, wearing a homemade Spider-Man suit while using suction cups, camming devices, and sky hooks, and despite several attempts by the Chicago Fire Department to stop him, made the first successful outside ascent of the tower. Goodwin was arrested at the top after the seven-hour climb and was later charged with trespassing. Goodwin stated that the reason he made the climb was to call attention to shortcomings in high-rise rescue and firefighting techniques. After a lengthy interrogation by Chicago's District Attorney and Fire Commissioner, Goodwin was officially released from jail.[188][189]

In August 1999, French urban climber Alain "Spiderman" Robert, using only his bare hands and bare feet, scaled the building's exterior glass and steel wall all the way to the top. A thick fog settled in near the end of his climb, making the last 20 stories of the building's glass and steel exterior slippery.[190]

Annually, since 2009, the Willis Tower has hosted SkyRise Chicago, the world's tallest indoor stair climb, as a charity event benefiting Shirley Ryan AbilityLab, where participants can (legally) climb the Willis Tower's 103-story staircase.[191]

Naming rights

 
West facade and entrance

Sears sold the tower in 1994 and vacated it by 1995, but retained naming rights through 2003. The new owners were rebuffed in renaming deals with CDW Corp in 2005 and the U.S. Olympic Committee in 2008. British insurance broker Willis Group Holdings leased more than 140,000 square feet (13,000 m2) of space on three floors in 2009. A Willis spokesman said the naming rights were obtained as part of the negotiations at no cost to Willis[192] and the building was renamed Willis Tower on July 16, 2009.[112]

The naming rights are valid for 15 years, so it is possible that the building's name could change again as soon as 2024.[193] The Chicago Tribune joked that the building's new name reminded them of the oft-repeated "What you talkin' 'bout, Willis?" catchphrase from the American television sitcom Diff'rent Strokes[112] and considered the name-change ill-advised in "a city with a deep appreciation of tradition and a healthy ego, where some Chicagoans still mourn the switch from Marshall Field's to Macy's".[194] This feeling was confirmed in a July 16, 2009, CNN article in which some Chicago-area residents expressed reluctance to accept the Willis Tower name,[195] and in an article that appeared in the October 2010 issue of Chicago magazine that ranked the building among Chicago's 40 most important, the author pointedly refused to acknowledge the name change and referred to the building as the "Sears Tower".[196] Time magazine called the name change one of the top 10 worst corporate name changes and pointed to negative press coverage by local news outlets and online petitions from angry residents.[197] The naming rights issue continued into 2013, when Eric Zorn noted in the Chicago Tribune that "We're stubborn about such things. This month marked four years since the former Sears Tower was re-christened Willis Tower, and the new name has yet to stick."[198]

Broadcasting

 
The tower's antennas

Many broadcast station transmitters are located at the top of Willis Tower. Each list is ranked by height from the top down. Stations at the same height on the same mast indicate the use of a diplexer into the same shared antenna. Due to its extreme height, FM stations (all class B) are very limited in power output.

Radio stations

East mast
  • 482 m:
    • WLIT FM 93.9 MHz main, 4.0 kW, AMFM
    • WCHI FM 95.5 backup, 3.1 kW, AMFM
  • 480 m: WBMX FM 104.3 main, 4.1 kW, CBS Radio
  • 476 m: WTMX FM 101.9 main, 4.2 kW, Hubbard
  • 474 m: WBBM FM 96.3 main, 4.2 kW, CBS Radio
  • 472 m:
    • WKSC FM 103.5 main, 4.3 kW, AMFM
    • WGCI FM 107.5 main, 3.7 kW, AMFM
  • 470 m: WFMT FM 98.7, 6.0 kW
  • 468 m: WLS FM 94.7 main, 4.4 kW
  • FCC query[199]
West mast

NOAA Weather Radio station KWO39 transmits off the tower at 162.550 MHz. Programmed by the National Weather Service Weather Forecast Office in Chicago, it is equipped with Specific Area Message Encoding (SAME), which sets off a siren on specially programmed weather radios to alert of an impending hazard.

Television stations

East mast
  • 515 m:
    • WLS-TV 7 analog, 55 kW, ABC Owned Television Stations (Analog Broadcast discontinued as of June 12, 2009. Now broadcasting only in digital.)
    • WLS-TV 7 permanent digital, 4.75 kW
  • 510 m:
    • WCPX-TV 43 digital, 200 kW, Ion Media Networks
    • WCPX-TV 38 analog, 3630 kW, Ion Media Networks (Analog Broadcast discontinued as of June 12, 2009. Now broadcasting only in digital.)
    • WJYS TV 36 digital, 145 kW, Oxford Media Group
    • WCIU-TV 27 digital, 15.1 kW, Weigel Broadcasting
  • 509 m:
    • WXFT-TV 59 temporary digital, 200 kW, Univision Communications
    • WXFT-TV 50 permanent digital, 230 kW, Univision Communications
  • 498 m:
    • WTTW TV 11 analog, 60.3 kW, Window To the World Communications (Analog Broadcast discontinued as of June 12, 2009. Now broadcasting only in digital.)
    • WBBM-TV 12 digital, 8 kW, CBS Television Stations
  • 480 m:
    • WFLD TV 31 digital backup, 475 kW, Fox Television Stations
    • WPWR-TV 51 digital backup, 508 kW, Fox Television Stations
  • 478 m: WGN-TV 19 digital backup, 310/229 kW, Tribune Broadcasting
  • 474 m:
    • WTTW TV 47 digital backup, 150 kW, Window To the World Communications
    • WLS-TV 52 digital backup, 220 kW, ABC Owned Television Stations
  • unknown: WESV-LD 40 digital, 37.2 kW, Trinity Christian Center of Santa Ana
  • FCC query[201]
West mast
  • 523 m: WPWR-TV 51 digital, 1000 kW, Fox Television Stations
  • 514 m, WLS-TV 52 temporary digital, 153.6 kW, ABC Owned Television Stations
  • 508 m, WMAQ-TV 29 digital, 350 kW, NBC Owned Television Stations
  • 494 m:
    • WMAQ-TV 5 analog, 20 kW (Analog Broadcast discontinued as of June 12, 2009. Now broadcasting only in digital.)
    • WPWR-TV 50 analog, 5000 kW (Analog Broadcast discontinued as of June 12, 2009. Now broadcasting only in digital.)
    • WXFT-TV 60 analog, 5000 kW, (Analog Broadcast discontinued as of June 12, 2009. Now broadcasting only in digital.)
  • 475 m: WFLD TV 31 digital, 690/1000 kW, Fox Television Stations
  • 473 m: WCIU-TV 26 analog, 5000 kW (Analog Broadcast discontinued as of June 12, 2009. Now broadcasting only in digital.)
  • 472 m:
    • WCIU-TV 27 digital, 590 kW, Weigel Broadcasting
    • WSNS-TV 44 analog 5000 kW, NBC Owned Television Stations (Analog Broadcast discontinued as of June 12, 2009. Now broadcasting only in digital.)
    • WSNS-TV 45 digital 467/665 kW, NBC Owned Television Stations
  • 465 m: WTTW TV 47 digital, 300 kW, Window To the World Communications
  • 455 m: WJYS TV 36 digital, 50 kW, Oxford Media Group
  • 453 m: WGN-TV 19 digital, 645 kW, Tribune Broadcasting
  • unknown:
    • WWME-CD 39 digital, 4.4 kW, Weigel Broadcasting
    • WEDE-CD 34 digital, 50 kW, First United
    • WMEU-CA 48 analog STA, 150 kW, Weigel Broadcasting
    • WMEU-LD 32 digital, 15 kW
  • FCC query[202]

Cultural depictions

The building has appeared in numerous films and television shows set in Chicago such as Ferris Bueller's Day Off, where Ferris and company visit the observation deck.[203] Late Night with Conan O'Brien introduced a character called The Sears Tower Dressed In Sears Clothing when the show visited Chicago in 2006.[204] The building is also featured in History Channel's Life After People, in which it and other human-made landmarks suffer from neglect without humans around, collapsing two hundred years after people are gone.[205]

In the 2008 film The Dark Knight, it is part of Gotham City.[206] In the 2011 film Transformers: Dark of the Moon, it is featured in a number of scenes.[207] In the 2013 film Man of Steel, the tower is the location of the offices of the Daily Planet.[208]

Position in Chicago's skyline

311 South WackerWillis TowerChicago Board of Trade Building111 South WackerAT&T Corporate CenterKluczynski Federal Building333 South WabashChase TowerThree First National PlazaMid-Continental PlazaRichard J. Daley CenterChicago Title and Trust Center77 West WackerPittsfield BuildingLeo Burnett BuildingThe Heritage at Millennium ParkCrain Communications BuildingIBM PlazaOne Prudential PlazaTwo Prudential PlazaAon CenterBlue Cross and Blue Shield Tower340 on the ParkPark TowerOlympia Centre900 North Michigan875 North Michigan AvenueWater Tower PlaceHarbor PointThe ParkshoreNorth Pier ApartmentsLake Point TowerJay Pritzker PavilionBuckingham FountainLake MichiganLake MichiganLake Michigan 

See also

References

Citations

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Sources

  • Kamin, Blair (2001). Why Architecture Matters: Lessons from Chicago. University of Chicago Press. ISBN 978-0-226-42322-7.
  • Pridmore, Jay; Larson, George A. (2018). Chicago Architecture and Design (3rd ed.). ABRAMS. ISBN 978-1-68335-421-5.

External links

 
Wikimedia Commons has media related to Willis Tower.
  • Official website Willis Tower office-space leasing website
  • Willis Tower Skydeck website
  • on CTBUH Skyscraper Center
  • . Emporis. Archived from the original on September 23, 2015.
  • Willis Tower at Structurae
Records
Preceded by Tallest building in the world
1,450 ft
1973–1998 		Succeeded by
World's tallest building architectural element
1,450 ft
1973–1998
Building with the most floors
108 floors
2001–2007 		Succeeded by
World's tallest building rooftop
1,450 ft
1973–2003 		Succeeded by
Tallest building in the United States
1,450 ft
1973–2013 		Succeeded by
Preceded by Tallest building in Chicago
1,450 ft
1973–present 		Incumbent

May 02, 2023
willis, tower, originally, sears, tower, story, foot, skyscraper, loop, community, area, chicago, illinois, united, states, designed, architect, bruce, graham, engineer, fazlur, rahman, khan, skidmore, owings, merrill, opened, 1973, world, tallest, building, t. The Willis Tower originally the Sears Tower is a 110 story 1 451 foot 442 3 m skyscraper in the Loop community area of Chicago in Illinois United States Designed by architect Bruce Graham and engineer Fazlur Rahman Khan of Skidmore Owings amp Merrill SOM it opened in 1973 as the world s tallest building a title that it held for nearly 25 years It is the third tallest building in the Western Hemisphere as well as the 23rd tallest in the world Each year more than 1 7 million people visit the Skydeck observation deck the highest in the United States making it one of Chicago s most popular tourist destinations 4 Willis TowerFormer namesSears Tower 1973 2009 Record heightTallest in the world from 1973 to 1998 I Preceded byWorld Trade CenterSurpassed byPetronas TowersGeneral informationStatusCompletedTypeOffice observation communicationArchitectural styleInternationalLocation233 S Wacker DriveChicago Illinois 60606United StatesCoordinates41 52 44 N 87 38 09 W 41 8789 N 87 6358 W 41 8789 87 6358 Coordinates 41 52 44 N 87 38 09 W 41 8789 N 87 6358 W 41 8789 87 6358Current tenantsUnited AirlinesNamed forWillis Towers WatsonSears 1973 2009 Construction started1970 53 years ago 1970 Completed1974 49 years ago 1974 OpeningSeptember 1973 49 years ago September 1973 OwnerBlackstone Group 2 HeightArchitectural1 451 ft 442 m 1 Tip1 729 ft 527 m 1 Top floor1 354 ft 413 m 1 Technical detailsFloor count108 3 basement floors 3 Floor area4 477 800 sq ft 416 000 m2 1 Lifts elevators104 1 with 16 double decker elevators made by Westinghouse modernized by Schindler Group and recently remodernized by Otis Elevator CompanyDesign and constructionArchitect s Skidmore Owings amp Merrill 1 Fazlur Rahman Khan Bruce GrahamEngineerJaros Baum amp Bolles MEP Aon Fire Protection Engineering formerly Schirmer Engineering Corporation Fire 1 Structural engineerSkidmore Owings amp MerrillMain contractorMorse Diesel InternationalReferencesI Willis Tower Emporis Archived from the original on September 23 2015 1 The building occupies a site bounded by Franklin Street Jackson Boulevard Wacker Drive and Adams Street Graham and Khan designed the building as nine square tubes clustered in a 3 3 matrix seven of the tubes set back at upper floors The tower has 108 stories as counted by standard methods though the building s owners count the main roof as 109 and the mechanical penthouse roof as 110 1 3 The facade is made of anodized aluminum and black glass The base of the building contains a retail complex known as the Catalog The lower half of the tower was originally occupied by retail company Sears which had its headquarters there until 1994 while the upper stories were rented out The structure was known as the Sears Tower from its construction until the naming rights were included in a 2009 lease with the Willis Group Local area residents still refer to the building by its old name 5 As of April 2018 update the building s largest tenant is United Airlines which occupies around 20 floors 6 7 8 Other major tenants include the building s namesake Willis Towers Watson and law firms Schiff Hardin and Seyfarth Shaw 8 Morgan Stanley became the building s fourth largest tenant in 2017 8 9 Contents 1 History 1 1 Planning 1 1 1 Site selection 1 1 2 Design process 1 2 Construction 1 2 1 Early construction 1 2 2 Broadcast signal controversy 1 2 3 Topping out and completion 1 3 20th century 1 3 1 Opening and early years 1 3 2 Renovation and relocation 1 4 21st century 1 4 1 Syndicate ownership 1 4 2 Blackstone ownership 1 5 Incidents 2 Architecture 2 1 Form and facade 2 2 Structural and mechanical features 2 2 1 Elevators and escalators 2 3 Interior 2 3 1 Base 2 4 Skydeck 3 Height 3 1 Climbing 4 Naming rights 5 Broadcasting 5 1 Radio stations 5 2 Television stations 6 Cultural depictions 7 Position in Chicago s skyline 8 See also 9 References 9 1 Citations 9 2 Sources 10 External linksHistoryPlanning Site selection Sears Roebuck amp Co had occupied an office complex on Chicago s west side since 1906 The existing offices were inadequate by 1966 prompting Sears executives to begin searching for a new site 10 By 1969 Sears was the largest retailer in the world with about 350 000 employees 11 Sears executives quickly determined that a new headquarters complex in the suburbs was infeasible since it would require relocating about 7 000 employees Instead Sears executives decided to consolidate the thousands of employees in offices distributed throughout the Chicago area into one building on the western edge of Chicago s Loop 10 12 Sears asked its outside counsel Arnstein Gluck Weitzenfeld amp Minow now known as Arnstein amp Lehr LLP to suggest a location The firm consulted with local and federal authorities and the applicable law then offered Sears two options 13 The first option was the Goose Island area northwest of the Loop but Sears s vice president of real estate Matthew J Stacom rejected this proposal The other was a two block area in the Loop bounded by Franklin Street on the east Jackson Boulevard on the south Wacker Drive on the west and Adams Street on the north Though the site was more centrally located it was also relatively small with about 55 000 square feet 5 100 m2 Bernard Feinberg Albert I Rubenstein and Philip Teinowitz had assembled that site over the previous five years but they had failed to acquire a neighboring 74 000 square foot 6 900 m2 lot from bus company Greyhound Lines 14 Feinberg Rubenstein and Teinowitz then bought options for three adjacent lots Under the terms of each option unless the three men were able to acquire at least one of the lots within 90 days all three options would be forfeited 14 Ultimately Sears acquired the Loop site in 1970 14 15 Sears then obtained permits to close down one block of Quincy Street which bisected the site from east to west Attorneys from the Arnstein firm headed by Andrew Adsit began buying the properties parcel by parcel 16 Sears purchased 15 buildings from 100 owners and paid the government of Chicago 2 7 million for the block of Quincy Street that was to be closed down 15 Design process Sears executives estimated that their new building would need about 4 2 million square feet 390 000 m2 split into 70 stories with 60 000 square feet 5 600 m2 each or 60 stories with 70 000 square feet 6 500 m2 each 10 Sears commissioned architecture firm Skidmore Owings amp Merrill SOM to design the tower 17 SOM was also the lead structural engineer and Jaros Baum amp Bolles provided MEP engineering 1 Sears planned to move its merchandise group into the building initially renting out the remaining space to other tenants until needed Sears executives were accustomed to large floor areas of at least 100 000 square feet 9 300 m2 but SOM architects raised concerns that the large floors would be unattractive to smaller tenants A subsequent proposal called for two buildings connected by a footbridge which would respectively contain 50 000 square feet 4 600 m2 and 30 000 square feet 2 800 m2 on each floor but this was also infeasible 17 Some floors were designed with smaller footprints to attract prospective lessees so the building s height was increased to meet Sears s floor area requirements 17 Architect Bruce Graham and structural engineer Fazlur Rahman Khan both of whom were partners with SOM proposed a tower with 55 000 square foot 5 100 m2 floors in the lower part of the building as well as a series of setbacks with gradually tapering floor plates giving the tower its distinctive look 18 During the design process one of the architects reportedly pulled out nine cigars and staggered them vertically until the pair both agreed to the arrangement 18 19 This allowed Sears to occupy the large lower stories while providing more conventional office space that could be rented out on the upper stories 20 The firm of Saphier Lerner Schindler was responsible for determining Sears s space requirements and designing furniture for the company 14 21 It conducted a year long study to determine how 16 of the company s departments should be laid out within the building 21 As Sears continued to offer optimistic growth projections the height of the proposed tower also increased 17 Under Chicago s relatively lax zoning laws the site could theoretically accommodate a 300 story building with 13 5 million square feet 1 250 000 m2 14 In practice most potential tenants did not want excessively high offices 14 Additionally the Federal Aviation Administration FAA restricted the height of structures in the area to protect air traffic 14 17 FAA officials publicly denied that they had imposed a height limit 22 however the area s minimum safe altitude would need to be raised by 1 000 feet 300 m if the building was just 1 foot 0 30 m taller 23 Plans for the tower were announced on July 27 1970 The 1 450 foot tall 440 m building would contain 109 stories as measured from Wacker Drive and 110 stories as measured from Franklin Street 15 24 This would make Sears s new tower the tallest in the world as measured by roof height although New York City s under construction World Trade Center Twin Towers would have a taller antenna 22 Although the Sears Tower would contain 4 4 million square feet 410 000 m2 of space only about 3 7 million square feet 340 000 m2 would be used as offices 24 Construction Early construction The Sears Tower now Willis Tower during its construction in 1973 Work on the building s foundation commenced in August 1970 Contractors excavated the lot to a depth of 50 feet 15 m and they removed 180 000 cubic feet 5 100 m3 of dirt from the site 25 By that November Spencer White amp Prentis Inc was excavating a trench around the site measuring 60 feet 18 m deep and 20 by 216 feet 6 1 by 65 8 m across The contractors then built a slurry wall within the trench made of concrete and reinforced steel 26 Workers used steel bracing to prevent the slurry wall from collapsing inward then used caissons to drill 201 holes into the ground They also rerouted a sewer that had run underneath Quincy Street which was to be closed permanent as part of the tower s construction 25 The Diesel Construction Company was hired as the Sears Tower s general contractor 27 Sears Roebuck amp Co chairman Gordon M Metcalf installed the building s first steel beam at a ceremony on June 7 1971 28 29 The project employed 2 000 workers To accelerate the building s construction a concrete plant was built in the building s basement allowing workers to pour one third of a concrete floor every day Contractors built two temporary kitchens on the site for workers and telephone and loudspeaker systems were installed on every floor to allow workers to communicate In addition contractors installed temporary generators that could supply up to 14 000 kilowatts 19 000 hp simultaneously during the winter most of this electricity was used to heat the exposed steel beams on the lowest five floors 30 Broadcast signal controversy By late 1971 Chicagoland residents and broadcasters had raised concerns that the new Sears Tower would disrupt television broadcasts 31 32 According to one estimate the building would obstruct television signals for 15 percent of Chicagoans and cause double images for another 20 percent 31 primarily affecting communities to the northwest and southeast 32 The same year officials of the village of Skokie northwest of Chicago threatened to request an injunction to prevent further construction 33 34 In response to these concerns Sears started researching methods to reduce the tower s effect on broadcast signals Variety magazine stated that the Sears Tower did not interfere with broadcasts on its own since several shorter towers in the Loop also interfered with broadcast signals 35 Nonetheless the Illinois Citizens Committee for Broadcasting filed a formal complaint with the Federal Communications Commission FCC in February 1972 36 37 The first lawsuit against the building was filed by the state attorney in neighboring Lake County on March 17 1972 38 39 A second suit was filed on March 28 in Cook County Circuit Court by the villages of Skokie Northbrook and Deerfield Illinois 39 40 Sears filed motions to dismiss the Lake and Cook County lawsuits which both sought to cap the building at 67 stories 40 Sears studied the possibility of erecting antennas atop its tower in April 1972 41 and the tower s construction continued even as decisions on both lawsuits were delayed 42 At the end of the month the company applied for permission to increase the building s height limit by 350 feet 110 m and install a new antenna 43 44 although eight of Chicago s ten television stations criticized the plan 45 46 On May 17 1972 Judge LaVerne Dickson Chief of the Lake County Circuit Court dismissed the suit saying I find nothing that gives television viewers the right to reception without interference 47 By then the building had reached the 58th story 48 The Lake County attorney appealed to the Illinois Supreme Court 48 In his decision on June 12 Judge Charles R Barrett contended the plaintiffs did not have a right to undistorted television reception 49 Meanwhile the FCC declined to act on the height dispute on the grounds it did not have jurisdiction 50 The FAA approved the antennas atop the tower in June 1972 51 52 and the Illinois Supreme Court affirmed the previous rulings by Lake and Cook County circuit courts at the end of the month 53 Work was temporarily paused that July due to a labor strike 54 The next month Sears formally announced plans for broadcast antennas on the tower s roof 55 56 and the company offered to spend 5 million to help relocate broadcast stations to the Sears Tower 55 The United States Court of Appeals for the Seventh Circuit upheld the FCC s decision in September 57 and the United States Supreme Court refused to hear an appeal of the Seventh Circuit s decision that November 58 59 Topping out and completion In November 1972 the Sears Tower became Chicago s tallest building 60 surpassing the Standard Oil Building which had held the record for one month 61 At the time the Sears project employed 1 600 workers in three shifts one worker had been killed during the project so far 27 60 The building s final completion had been delayed significantly due to labor strikes and bad weather The concrete work had reached the 77th floor while the steel superstructure had reached the 84th floor the remainder of the steelwork would be difficult to construct because of high winds at higher altitudes 60 Local television stations WTTW and WLS TV were planning to install temporary broadcast antennas atop the tower when the steel frame was completed 62 The tower s superstructure had reached the 100th floor in February 1973 at which point it was taller than the Empire State Building in New York City 63 The building was topped out on May 3 1973 64 The day before the event the Chicago Tribune s editorial board wrote Move aside New York After tomorrow when schoolchildren dream of big buildings they ll no longer think of you and the Empire State Building and the World Trade Center 65 The frame was still not technically complete as three to four stories remained to be built 66 One week after the ceremony four workers died after an elevator shaft caught fire 66 67 A fifth worker died after falling from the tower in an unrelated incident four days later 68 Work was halted again that June due to a labor strike 69 70 and Sears began moving furniture into the building that month 71 The construction cost was about US 150 million 72 equivalent to 920 million in 2021 dollars 73 Despite the size of the project Sears executives said the building could not accommodate Sears annual shareholder meetings and the company continued to rent space in other structures 74 20th century Opening and early years The first Sears employees began moving into the tower during the weekend of September 9 1973 71 75 Flashing beacons on the building s roof the first to be installed at any building in Chicago were activated the same month 76 Upon the tower s opening broadcasters at the John Hancock Center Chicago s second tallest building had to decide whether to relocate to the Sears Tower 77 Two television stations decided to relocate 78 Six other stations remained at the John Hancock Center citing a study which showed that relocating to the Sears Tower would provide only minimal benefits 78 79 Documents released in late 1973 indicated that the Sears Tower would cause much more interference than either Sears or the television stations had disclosed 79 WLS TV moved to the Sears Tower in February 1974 80 followed by WTTW the next month 81 By March 1974 three fourths of the space in the building was occupied Sears had leased the upper stories to tenants such as Goldman Sachs Northwest Industries and Schiff Hardin 82 A mobile sculpture by Alexander Calder was dedicated in the lobby in October 1974 83 84 Sears optimistic growth projections were not realized instead in late 1974 the company fired 500 workers about seven percent of the 7 000 Sears employees that worked in the tower 85 Competition beyond its traditional rivals such as Montgomery Ward arose from emerging retail giants including Kmart Kohl s and Walmart As a result of a surplus of office space that emerged in the 1980s the tower did not draw as many tenants as projected and so stood half vacant for a decade Renovation and relocation The tower in 1978 after its completion In February 1984 Sears announced that it would renovate the building to attract visitors to the lower floors 86 87 At the time 6 500 Sears employees occupied more than half of the building 87 88 taking up the lowest 48 stories 88 The remainder of the tower was occupied by 5 500 employees from about 70 companies 87 As part of the project the main entrance was covered with a four story glass dome and the first four stories were converted into a shopping atrium In addition a visitor center for the building s Skydeck was constructed 86 87 The renovations designed by SOM were completed in mid 1985 88 Paul Gapp of the Chicago Tribune wrote that SOM had scaled the new entrance skillfully in keeping with the main building s height and that the new atrium relieves the formerly cramped feeling from just inside the Franklin entrance 89 Sears announced in 1988 that it would sell the tower and relocate its merchandising division from the lower half of the building 90 The company wanted to earn at least 1 billion from the sale of the Sears Tower so it offered multiple concessions to potential buyers including a guarantee that Sears would continue to pay rent on the lower half of the building until tenants were found for these stories 91 Four large firms were negotiating to buy the tower by July 1989 92 The company had difficulties finding a buyer in part because the lower stories were too large for many potential tenants 93 Sears nearly sold the tower to Canadian company Olympia amp York but the deal was canceled in September 1989 because the two firms could not agree on who would pay the property taxes 94 In November 1989 Sears decided to instead refinance the building 95 The next year Sears took out a mortgage loan on the tower for 850 million from MetLife and AEW Capital Management with MetLife as the holder of the mortgage note the loan would mature in 2005 96 In 1990 the law firm of Keck Mahin amp Cate decided to move into a development that would become 77 West Wacker Drive rebuffing Sears attempts to entice the firm to stay 97 Just two years later Sears began moving its own offices out of the building 98 to a new campus in Hoffman Estates Illinois which was completed in 1995 96 As the maturation of the mortgage approached Sears renegotiated the loan in 1994 The negotiations resulted in an agreement where Sears would no longer be liable for the 850 million loan although it would only nominally own the building while AEW and MetLife effectively had total control As part of the 1994 agreement AEW and MetLife would be able to take official ownership of the building in 2003 96 In 1997 Toronto based TrizecHahn at the time the lessee of the CN Tower acquired AEW s holdings in the building for 110 million assuming 4 million in liabilities and a 734 million mortgage 99 100 21st century Trizec had projected that the Sears Tower would quickly reach a value of 1 billion These projections were not met with the tower facing the same vacancy and other problems it saw under Sears although Trizec made somewhat successful efforts to attract new tenants Following the September 11 attacks two of the largest tenants Goldman Sachs and Merrill Lynch immediately announced plans for vacating 300 000 ft2 of space In 2003 Trizec sold its holdings of the tower to MetLife for 9 million 101 Syndicate ownership In March 2004 MetLife announced that it would sell the building to a group of investors 102 103 including Joseph Chetrit Joseph Moinian Lloyd Goldman Joseph Cayre and Jeffrey Feil of New York as well as American Landmark Properties of Skokie Illinois 104 The quoted price was 840 million with 825 million held in a mortgage 105 Two years later in February 2007 the Sears Tower s owners obtained a 780 million loan from UBS 106 At the time UBS valued the tower at 1 2 billion 107 The tower at night in 2009 Since 2007 the owners had considered plans for the construction of a hotel on the north side of Jackson Boulevard between Wacker Drive and Franklin Street close to the entrance of the observation deck above the tower s underground parking garage According to the tower s owners the second building was considered in the original design The plan was eventually cancelled as city zoning did not permit construction of such a tall building in that location 108 In February 2009 the owners announced they were considering a plan to paint the structure silver an idea that was later abandoned It was hoped that a new silver paint job would rebrand the building and highlight its advances in energy efficiency for an estimated cost of 50 million 109 Although Sears naming rights expired in 2003 the building continued to be called the Sears Tower for several years despite multiple changes in ownership In March 2009 London based insurance broker Willis Group Holdings agreed to lease a portion of the building and obtained the naming rights 110 111 On July 16 2009 the building was officially renamed the Willis Tower 112 113 By 2011 the building s owners were considering selling a partial ownership stake or even the entire building to an investor 114 The next year United Airlines announced it would move its corporate headquarters from 77 West Wacker Drive to Willis Tower 6 Blackstone ownership By March 2015 the Willis Tower was being marketed at a price of 1 5 billion 115 The same month the Blackstone Group purchased the tower for a reported 1 3 billion the highest price ever paid for a property in the U S outside of New York City 116 117 Blackstone announced a 500 million renovation in January 2017 which would include the construction of the Catalog a six story commercial complex replacing a plaza on Jackson Boulevard and the entrance on Wacker Drive 118 119 Architectural firm Gensler designed the renovation 120 121 A rooftop terrace was built atop the Catalog and the building s HVAC systems were overhauled 120 Most of the building s elevators excluding those that served the Skydeck were also renovated for the first time in the tower s history The new elevators would be faster than the original elevators and would use use 35 percent less energy 122 123 The building s owners installed artwork by Olafur Eliasson Jacob Hashimoto and other artists 120 To fund these improvements in February 2017 Blackstone obtained a 1 billion loan from a group of banks including Goldman Sachs The new loan replaced 750 million of CMBS debt that was maturing 124 The following year because of the increasing costs of the renovation 125 Blackstone received a new 1 3 billion loan from Deutsche Bank and Barclays 126 127 The Wacker Drive entrance was demolished in early 2018 to make way for the Catalog 128 A steel globe next to the entrance manufactured by the Poblocki Sign Company and installed in 2010 was relocated to Elmhurst Illinois 128 129 A 40 000 square foot 3 700 m2 private club on the 66th and 67th stories opened in June 2018 The club included a restaurant named Craftsman and a lounge named Frame both of which exclusively served the tower s tenants as well as a public restaurant known as the East Room 130 131 That September Urbanspace announced that it would operate a food hall on the lower stories 132 133 In 2020 insurance company Aon had proposed acquiring Willis Towers Watson which had succeeded the Willis Group as the building s owner 134 135 prompting speculation that the building could be renamed again 136 The planned merger was canceled in 2021 following an antitrust lawsuit from the United States Department of Justice 137 The building s renovation was completed in May 2022 120 138 139 At the time although the Willis Tower was nearly 85 percent leased the number of tenants and visitors entering the building had decreased significantly since 2019 in part because of the COVID 19 pandemic in Chicago 120 In April 2023 the New York Times reported that Blackstone had written down the value of its investment in the tower by 119 million 140 Incidents In June 2006 seven men were arrested by the FBI and charged with plotting to destroy the tower Deputy FBI Director John Pistole described their plot as more aspirational than operational 141 142 The case went to court in October 2007 143 After three trials five of the suspects were convicted and two acquitted 144 The alleged leader of the group Narseal Batiste was sentenced to 13 1 2 years in prison 145 In response to the perceived threat of an attack the building s largest tenant at this time Ernst amp Young moved to North Wacker Drive in early 2009 146 In May 2020 heavy rains caused three of the basement levels to flood knocking out power to the building This also resulted in many TV and radio stations going off the air 147 Architecture Breakdown of the bundled tube structure of Willis Tower with simplified floor plans The Willis Tower was designed by architect Bruce Graham and structural engineer Fazlur Rahman Khan of Skidmore Owings and Merrill 148 Graham and Khan designed the building as nine square tubes clustered in a 3 3 matrix forming a square base with 225 foot 69 m sides 17 18 The building s total area is 3 787 200 sq ft 351 800 m2 149 The structure was intended to accommodate 16 500 employees 150 Form and facade Each of the tubes is a column free module measuring 75 by 75 feet 23 by 23 m 151 which set back at different stories 19 There are setbacks at the 50th 66th and 90th floors 84 152 12 The lowest 50 stories contain nine tubes and cover 52 000 square feet 4 800 m2 each 17 18 20 The northwest and southeast tubes terminate at the 50th floor The 51st through 66th floors each span 41 420 square feet 3 848 m2 above which the northeast and southwest tubes end From the 67th to 90th floors each story is shaped like a cross covering 30 170 square feet 2 803 m2 The north east and south tubes end at the 90th floor the remaining west and center tubes reach 108 floors with an area of 12 283 square feet 1 141 1 m2 on each of the top stories 17 Sculpture honoring Fazlur Rahman Khan considered the father of tubular designs at the Willis Tower Khan is known for making important advancements in skyscraper engineering The Sears Tower was the first building to use this innovative design It was both structurally efficient and economic at 1 450 feet it provided more space and rose higher than the Empire State Building and cost much less per unit area 153 The system would prove highly influential in skyscraper construction and has been used in most supertall buildings since including the world s current tallest building the Burj Khalifa 154 155 In February 1982 two television antennas were added to the structure increasing its total height to 1 707 feet 520 3 m The western antenna was later extended bringing the overall height to 1 729 feet 527 m 1 on June 5 2000 to improve reception of local NBC station WMAQ TV The perimeter of the Willis Tower contains columns that are spaced 15 feet 4 6 m apart on their centers The facade is made of anodized aluminum and black glass 84 152 Alcoa manufactured 4 million pounds 1 8 kt of aluminum sheeting for the building s facade 156 Black bands appear on the tower around the 29th 32nd 64th 65th 88th 89th and 104th 108th floors These elements are louvers to ventilate the building s environmental support systems and obscure its belted trusses 157 The rest of the facade is made of 16 000 rectangular windows 158 159 all of which measure 5 by 8 feet 1 5 by 2 4 m and are tinted with bronze 159 Outside the building there was originally a 80 000 square foot 7 400 m2 plaza made of pink granite 158 In the late 2010s a three level wing was built along the western and southern sides of the tower replacing the tower The roof garden above the annex spans 30 000 square feet 2 800 m2 121 160 The annex contains a facade of black steel and aluminum similar to in the original building 121 The Jackson Boulevard facade of the annex contains an artwork by Olafur Eliasson entitled Atmospheric wave wall 161 162 The work measuring 30 by 60 feet 9 1 by 18 3 m across 161 comprises almost 2 000 blue and green steel tiles which are decorated with hexagonal motifs 162 163 The wall is backlit at night 161 162 Structural and mechanical features The interior includes 74 000 short tons 66 000 long tons 67 000 t of steel 4 million pounds 1 8 kt of aluminum and 101 acres 4 400 000 sq ft 410 000 m2 of concrete flooring 159 27 The building contains diagonal columns only on the two stories immediately below each of the setbacks thus reducing shear stress 152 The interior of the building could not contain diagonal beams since these would have obstructed the connections between each of the tubes Therefore the columns and the horizontal beams on each story are connected by rigid joints 84 The superstructure was designed to withstand wind gusts of 130 miles per hour 210 km h which on average would occur once every hundred years 150 According to the Chicago Tribune the top of the building would be able to bend by as much as 7 inches 180 mm returning to its normal position within 7 2 seconds 158 The Willis Tower s basement extends 50 feet 15 m deep resting on a 5 foot thick 1 5 m concrete slab The ground directly beneath the building was largely made of clay the underlying layer of limestone was as much as 100 feet 30 m beneath ground level 25 As a result the foundation was excavated using 201 caissons 25 23 of which 114 reached the underlying limestone 23 The caissons created holes that measured up to 10 feet 3 0 m across Some holes at the northwestern and northeastern corners of the site filled up with groundwater and had to be drained Workers next placed steel tubes into the holes then poured concrete around the tubes 25 During the Sears Tower s construction SOM and Chicago government officials considered adding smoke free and fire free areas to the building as well as a complete sprinkler system serving all floors Neither of these features had previously been used in a structure in Chicago 164 Even though regulations did not require a fire sprinkler system the building was equipped with one from the beginning There are around 40 000 sprinkler heads in the building installed at a cost of 4 million 157 When it was completed the Sears Tower was heated electrically unlike older structures that used gas heating 165 It included 145 000 light fixtures and a cooling system capable of 17 000 tons of refrigeration 27 12 Furthermore the tower contained fire suppression and communications systems for emergency use which were powered by diesel generators 150 166 If there was a fire in one section of the building the building s smoke detection system would close off the fresh air intake openings in that section discharging smoke outdoors 150 Fifteen above ground stories as well as three of the basement levels contain mechanical equipment Above the Skydeck on the 103rd floor is a seven story mechanical penthouse 12 Elevators and escalators The Sears Tower was planned with 103 elevators 150 158 including 14 double deck elevators 150 167 The office stories are served by 97 elevator cabs due to the presence of the double deck elevators these occupy 83 shafts 123 As designed one bank of single deck elevators connected the lobby to the lowest 28 stories 167 Banks of double deck elevators traveled to sky lobbies at the 33rd 34th and 66th 67th floors where passengers could transfer to local elevators The 34th through 103rd stories were served by local elevators that operated from the sky lobbies 150 167 Two elevators also ran directly from the lobby to the Skydeck on the 103rd floor 168 As of 2018 update the elevators carried 5 8 million passengers per year 122 123 Six of the elevators are used for freight 158 One of the freight elevators served all stories traveling to a height of 1 440 feet 440 m 168 During a fire or another emergency this elevator would be reserved for the Chicago Fire Department Other elevators would be controlled from the 33rd floor During a fire elevators would be dispatched to the affected floors to assist with evacuation 150 The building also had 16 escalators including a set of double height escalators that traveled from the main lobby to the lower mezzanine 167 Another set of escalators connects the 33rd and 34th stories 158 Interior Base Bottom of the tower When the building was completed the main entrance was on Wacker Drive to the west There was a plaza on the south side of the building sloping upward toward Franklin Street to the east The Franklin Street side of the building was 6 feet 1 8 m lower than the Wacker Drive entrance so the entrances on Franklin Street were actually below the plaza leading to the building s lower mezzanine 167 Below ground level are three basement levels with a total area of 400 000 square feet 37 000 m2 14 The basements included a 1 200 seat cafeteria commercial space service areas and a loading dock for 17 trucks 84 The basement also contained a 150 spot parking garage 158 As of 2022 update the building s base covers 463 000 square feet 43 000 m2 and contains two lobbies for tenants 120 121 The building s tenants primarily enter from Wacker Drive and Franklin Street Shoppers restaurant patrons and visitors to the Skydeck observation deck use the southern entrance on Jackson Boulevard 160 The Wacker Drive lobby contains In the Heart of this Infinite Particle of Galactic Dust a 2019 artwork by Jacob Hashimoto It consists of over 7 000 rice paper and resin disks that are hung from the ceiling 161 169 To honor Khan s contributions to skyscraper engineering design the Structural Engineers Association of Illinois also commissioned a sculpture of him for the lobby of the Willis Tower 170 The commercial complex at the building s lowest stories is known as the Catalog a reference to Sears mail order catalogs 121 171 The six story complex includes numerous restaurants 171 It extends into three of the building s basement levels as well as the three story annex to the south and west of the tower 121 The roof of the annex includes a curved skylight with 240 glass panes and the northern section of the annex s roof is supported by black columns that resemble those in the original tower The Catalog also contains decorative details such as handrails and staircase landings which are inspired by elements of Chicago s built environment 172 The third story of the Catalog contains a 30 000 square foot coworking space operated by Convene 160 172 Skydeck Four glass bottom skyboxes on the west facade of Willis Tower at the 103rd floor Glass balcony at the Skydeck The Willis Tower observation deck called the Skydeck opened on June 22 1974 Located on the 103rd floor 1 353 feet 412 4 m above ground level it is the highest observation deck in the United States 173 and one of Chicago s most famous tourist attractions 174 Tourists can experience how the building sways in wind and see far over the plains of Illinois and across Lake Michigan to Indiana Michigan and Wisconsin in clear conditions Elevators reach the top in about 60 seconds allowing occupants to feel the change in pressure as they ascend The Skydeck competes with the John Hancock Center s observation floor a mile and a half away but reaching 323 feet 98 5 m lower Some 1 7 million tourists visit annually A second observation deck on the 99th floor serves as a backup In January 2009 a major renovation of the Skydeck began including the installation of retractable glass balconies which extend approximately 4 feet 1 2 m from the facade of the 103rd floor overlooking South Wacker Drive The all glass boxes informally dubbed The Ledge allow visitors to see the street below The boxes which can accommodate 5 short tons 4 5 metric tons opened to the public on July 2 2009 175 176 On May 29 2014 the laminated glass flooring of one of the boxes cracked while visitors were inside but there were no injuries 177 The flooring of the same box cracked again on June 12 2019 178 In May 2022 a fifth glass ledge opened on the west facade overlooking South Wacker Drive Panorama of Chicago skyline as seen from Willis Tower SkydeckHeight Height comparison with left to right Burj Khalifa Dubai CN Tower Toronto Willis Tower Chicago When completed the Sears Tower was the world s tallest building but not the world s tallest structure Toronto s CN Tower was about 350 feet 106 7 m taller 179 although the Council on Tall Buildings and Urban Habitat CTBUH does not consider the CN Tower to be a building since it does not have floors from the ground up 180 The Willis Tower remains the third tallest building in the Americas and in the Western Hemisphere after One World Trade Center and Central Park Tower in New York City With a pinnacle height of 1 729 feet 527 m it is the third tallest freestanding structure in the Americas 1 It is the 16th tallest freestanding structure in the world by pinnacle height When the Petronas Twin Towers in Kuala Lumpur Malaysia was completed in 1998 it claimed to be the tallest building in the world measuring 1 482 6 feet 451 9 m tall including decorative spires Chicagoans objected to this claim on the basis that the Sears Tower s top floor was higher than that of either of the Petronas Towers 181 In the ensuing controversy four categories of tallest building were created Of these Petronas was the tallest in the category of height to the top of architectural elements meaning spires but not antennas 181 182 Taipei 101 in Taiwan claimed the record in three of the four categories in 2004 surpassing the Petronas Twin Towers in spire height and the Sears Tower in roof height and highest occupied floor People suggested that Sears add cosmetics atop its tower to surpass Taipei 101 but this did not materialize 183 184 On August 12 2007 the Burj Khalifa in Dubai was reported by its developers to have surpassed the tower in all height categories 185 Upon completion One World Trade Center in New York City surpassed the Willis Tower through its structural and pinnacle heights but not by roof observation deck elevation or highest occupied floor 186 Until 2000 the tower did not hold the record for being the tallest building by pinnacle height From 1969 to 1978 this record was held by John Hancock Center whose antenna reached a height of 1 500 feet 457 2 m 49 feet 14 9 m taller than the Sears Tower s original height One World Trade Center became taller by pinnacle height with the addition of a 359 foot 109 4 meter antenna bringing its total height to 1 727 feet 526 4 m In 1982 two antennas were installed which brought its total height to 1 707 feet 520 3 m making it taller than the John Hancock Center but not One World Trade Center However the extension of the tower s western antenna in June 2000 to 1 729 feet 527 m allowed it to just barely claim the title of tallest building by pinnacle height The lowest level of Willis Tower is 43 feet 13 m below the elevation of Franklin Street 187 Climbing View of the wall of the tower from the Skydeck On May 25 1981 Dan Goodwin wearing a homemade Spider Man suit while using suction cups camming devices and sky hooks and despite several attempts by the Chicago Fire Department to stop him made the first successful outside ascent of the tower Goodwin was arrested at the top after the seven hour climb and was later charged with trespassing Goodwin stated that the reason he made the climb was to call attention to shortcomings in high rise rescue and firefighting techniques After a lengthy interrogation by Chicago s District Attorney and Fire Commissioner Goodwin was officially released from jail 188 189 In August 1999 French urban climber Alain Spiderman Robert using only his bare hands and bare feet scaled the building s exterior glass and steel wall all the way to the top A thick fog settled in near the end of his climb making the last 20 stories of the building s glass and steel exterior slippery 190 Annually since 2009 the Willis Tower has hosted SkyRise Chicago the world s tallest indoor stair climb as a charity event benefiting Shirley Ryan AbilityLab where participants can legally climb the Willis Tower s 103 story staircase 191 Naming rights West facade and entrance Sears sold the tower in 1994 and vacated it by 1995 but retained naming rights through 2003 The new owners were rebuffed in renaming deals with CDW Corp in 2005 and the U S Olympic Committee in 2008 British insurance broker Willis Group Holdings leased more than 140 000 square feet 13 000 m2 of space on three floors in 2009 A Willis spokesman said the naming rights were obtained as part of the negotiations at no cost to Willis 192 and the building was renamed Willis Tower on July 16 2009 112 The naming rights are valid for 15 years so it is possible that the building s name could change again as soon as 2024 193 The Chicago Tribune joked that the building s new name reminded them of the oft repeated What you talkin bout Willis catchphrase from the American television sitcom Diff rent Strokes 112 and considered the name change ill advised in a city with a deep appreciation of tradition and a healthy ego where some Chicagoans still mourn the switch from Marshall Field s to Macy s 194 This feeling was confirmed in a July 16 2009 CNN article in which some Chicago area residents expressed reluctance to accept the Willis Tower name 195 and in an article that appeared in the October 2010 issue of Chicago magazine that ranked the building among Chicago s 40 most important the author pointedly refused to acknowledge the name change and referred to the building as the Sears Tower 196 Time magazine called the name change one of the top 10 worst corporate name changes and pointed to negative press coverage by local news outlets and online petitions from angry residents 197 The naming rights issue continued into 2013 when Eric Zorn noted in the Chicago Tribune that We re stubborn about such things This month marked four years since the former Sears Tower was re christened Willis Tower and the new name has yet to stick 198 Broadcasting The tower s antennas Many broadcast station transmitters are located at the top of Willis Tower Each list is ranked by height from the top down Stations at the same height on the same mast indicate the use of a diplexer into the same shared antenna Due to its extreme height FM stations all class B are very limited in power output Radio stations East mast482 m WLIT FM 93 9 MHz main 4 0 kW AMFM WCHI FM 95 5 backup 3 1 kW AMFM 480 m WBMX FM 104 3 main 4 1 kW CBS Radio 476 m WTMX FM 101 9 main 4 2 kW Hubbard 474 m WBBM FM 96 3 main 4 2 kW CBS Radio 472 m WKSC FM 103 5 main 4 3 kW AMFM WGCI FM 107 5 main 3 7 kW AMFM 470 m WFMT FM 98 7 6 0 kW 468 m WLS FM 94 7 main 4 4 kW FCC query 199 West mast460 amp 451 m WFMT FM 98 7 backups 443 m WBBM FM 96 3 backup WBMX 104 3 backup W264BF simulcast of WHLP 100 7 MHz 2 W Calvary Chapel of Costa Mesa table of allotments WLIT WLS WBBM WTMX WBMX WCFS FCC query 200 NOAA Weather Radio station KWO39 transmits off the tower at 162 550 MHz Programmed by the National Weather Service Weather Forecast Office in Chicago it is equipped with Specific Area Message Encoding SAME which sets off a siren on specially programmed weather radios to alert of an impending hazard Television stations East mast515 m WLS TV 7 analog 55 kW ABC Owned Television Stations Analog Broadcast discontinued as of June 12 2009 Now broadcasting only in digital WLS TV 7 permanent digital 4 75 kW 510 m WCPX TV 43 digital 200 kW Ion Media Networks WCPX TV 38 analog 3630 kW Ion Media Networks Analog Broadcast discontinued as of June 12 2009 Now broadcasting only in digital WJYS TV 36 digital 145 kW Oxford Media Group WCIU TV 27 digital 15 1 kW Weigel Broadcasting 509 m WXFT TV 59 temporary digital 200 kW Univision Communications WXFT TV 50 permanent digital 230 kW Univision Communications 498 m WTTW TV 11 analog 60 3 kW Window To the World Communications Analog Broadcast discontinued as of June 12 2009 Now broadcasting only in digital WBBM TV 12 digital 8 kW CBS Television Stations 480 m WFLD TV 31 digital backup 475 kW Fox Television Stations WPWR TV 51 digital backup 508 kW Fox Television Stations 478 m WGN TV 19 digital backup 310 229 kW Tribune Broadcasting 474 m WTTW TV 47 digital backup 150 kW Window To the World Communications WLS TV 52 digital backup 220 kW ABC Owned Television Stations unknown WESV LD 40 digital 37 2 kW Trinity Christian Center of Santa Ana FCC query 201 West mast523 m WPWR TV 51 digital 1000 kW Fox Television Stations 514 m WLS TV 52 temporary digital 153 6 kW ABC Owned Television Stations 508 m WMAQ TV 29 digital 350 kW NBC Owned Television Stations 494 m WMAQ TV 5 analog 20 kW Analog Broadcast discontinued as of June 12 2009 Now broadcasting only in digital WPWR TV 50 analog 5000 kW Analog Broadcast discontinued as of June 12 2009 Now broadcasting only in digital WXFT TV 60 analog 5000 kW Analog Broadcast discontinued as of June 12 2009 Now broadcasting only in digital 475 m WFLD TV 31 digital 690 1000 kW Fox Television Stations 473 m WCIU TV 26 analog 5000 kW Analog Broadcast discontinued as of June 12 2009 Now broadcasting only in digital 472 m WCIU TV 27 digital 590 kW Weigel Broadcasting WSNS TV 44 analog 5000 kW NBC Owned Television Stations Analog Broadcast discontinued as of June 12 2009 Now broadcasting only in digital WSNS TV 45 digital 467 665 kW NBC Owned Television Stations 465 m WTTW TV 47 digital 300 kW Window To the World Communications 455 m WJYS TV 36 digital 50 kW Oxford Media Group 453 m WGN TV 19 digital 645 kW Tribune Broadcasting unknown WWME CD 39 digital 4 4 kW Weigel Broadcasting WEDE CD 34 digital 50 kW First United WMEU CA 48 analog STA 150 kW Weigel Broadcasting WMEU LD 32 digital 15 kW FCC query 202 Cultural depictionsThe building has appeared in numerous films and television shows set in Chicago such as Ferris Bueller s Day Off where Ferris and company visit the observation deck 203 Late Night with Conan O Brien introduced a character called The Sears Tower Dressed In Sears Clothing when the show visited Chicago in 2006 204 The building is also featured in History Channel s Life After People in which it and other human made landmarks suffer from neglect without humans around collapsing two hundred years after people are gone 205 In the 2008 film The Dark Knight it is part of Gotham City 206 In the 2011 film Transformers Dark of the Moon it is featured in a number of scenes 207 In the 2013 film Man of Steel the tower is the location of the offices of the Daily Planet 208 Position in Chicago s skyline See also Chicago portal Illinois portal Architecture portalArchitecture of Chicago List of buildings with 100 floors or more List of tallest buildings and structures in the world List of tallest buildings by U S state List of tallest buildings in Chicago List of tallest buildings in the United States List of tallest buildings List of tallest freestanding structures in the world List of tallest freestanding steel structures List of tallest towers in the world Sears Roebuck and Company ComplexReferencesCitations a b c d e f g h i j k l Willis Tower The Skyscraper Center Council on Tall Buildings and Urban Habitat June 13 2015 Archived from the original on December 23 2019 Retrieved June 13 2015 de la Merced Michael J March 16 2014 Blackstone Group Purchases Landmark Willis Tower in Chicago The New York Times Retrieved August 11 2015 a b History and Facts Willis Tower willistower com Willis Tower owner seeks thousands of new visitors per day as 500 million expansion takes shape Chicago Tribune Retrieved October 19 2022 McClelland Edward June 5 2019 Chicagoans Refuse to Call These Places by Their Real Names Chicago Magazine Chicago Magazine Retrieved May 19 2021 a b 1 Archived August 15 2012 at the Wayback Machine Snyder Brett December 16 2013 A Day with United Management Elite Status Mileage Devaluation and Increasing Change Fees The Cranky Flier Retrieved December 18 2013 a b c Ecker Danny April 16 2018 Morgan Stanley moving second office to Willis Tower Crain s Chicago Business Retrieved October 3 2018 20 years after 9 11 a new crisis looms for Willis Tower Crain s Chicago Business September 1 2021 Retrieved January 25 2022 a b c Hoyt Monty May 25 1973 Sears Tower of tubes sets bundle of records Unique structure The Christian Science Monitor p 12 ProQuest 511528132 Kerch Steve October 20 1991 This job is a tall order Sears Tower project is the height of redevelopment Chicago Tribune a b c d The Tallest Building The Washington Post Times Herald August 26 1973 p L10 ISSN 0190 8286 ProQuest 148369539 Arnstein amp Lehr The First 120 Years a b c d e f g h The World s Tallest Saga of a Chicago Skyscraper The New York Times October 18 1970 ISSN 0362 4331 Retrieved September 7 2022 a b c Nagelberg Alvin July 28 1970 Sears to Construct Tallest Building In World 110 Stories Chicago Tribune pp 1 35 Retrieved August 24 2022 Chicago Tribune December 28 2003 a b c d e f g h Nagelberg Alvin August 2 1970 Sears Tower New Heights of Design Will Blend Advanced Concepts Chicago Tribune p 97 Retrieved August 24 2022 a b c d The Tallest Skyscraper TIME March 8 2008 Archived from the original on March 8 2008 Retrieved September 12 2022 a b Pridmore amp Larson 2018 p 182 a b Tower Will Withstand High Wind Chicago Tribune August 30 1970 p 97 Retrieved September 7 2022 a b Nagelberg Alvin September 20 1970 Building Sears Tower A Real Inside Job Chicago Tribune p C16 ProQuest 169878110 a b Martin Paul R January 20 1971 A Rising Competition It s Hard to Say Which Is Tallest Building Trade Center and Sears Building Vie but Won t Admit It Should a TV Tower Count The Wall Street Journal p 1 ISSN 0099 9660 ProQuest 133622903 a b c Arthur Art July 1 1971 Sears Is Now Tallest The Austin Statesman p A13 ProQuest 1521729590 a b New Sears Building in Chicago Planned as the World s Tallest The New York Times July 28 1970 ISSN 0362 4331 Retrieved September 7 2022 a b c d e Build Foundation of Huge Sears Tower Chicago Tribune April 18 1971 p D1 ProQuest 169075911 New Methods Speed Construction Chicago Tribune November 22 1970 p 105 Retrieved September 7 2022 a b c d Brown Terry P March 22 1973 A Tall Order How Big Ray Worley A Screamer and Yeller Is Building Sears Tower The Wall Street Journal p 1 ISSN 0099 9660 ProQuest 133809828 Set First Sears Tower Steel Chicago Tribune June 8 1971 p 53 Retrieved September 7 2022 First Steel in Sears Building The New York Times June 8 1971 ISSN 0362 4331 Retrieved September 7 2022 Sears Tower Uses Unique New Systems Chicago Tribune October 3 1971 p 97 Retrieved September 7 2022 a b Roth Morry November 24 1971 Radio Television Chicago Group Bids Stations Take Stand Vs Now Building Sears Tower Variety Vol 265 no 2 p 44 ProQuest 1014881361 a b Horton Luci November 25 1971 Your TV on the Blink Blame Sears Tower That Is Chicago Tribune p 163 Retrieved September 7 2022 Osbon John August 9 1971 Tv Ghosts May Haunt New Sears Tower Women s Wear Daily Vol 123 no 27 p 30 ProQuest 1862362537 Sluis William July 16 1971 Sears Tower Faces Suit Over TV Effect Chicago Tribune p A13 ProQuest 169116946 Retrieved September 7 2022 Roth Morry December 29 1971 Radio Television TV Operators In Chi Prefer To Pass Their Own Roebuck Bounce Back On Group Protesting Tall Sears Tower Variety Vol 265 no 7 p 23 ProQuest 962900933 Roth Morry February 23 1972 Local TV Radio amp Syndication Chicago Broadcast Group Works Up To 110 Story 19 Of Wrongs On Sears Tower For Weighing By FCC Variety Vol 266 no 2 p 44 ProQuest 962940770 U S Asked to Act in Sears TV Battle Chicago Tribune February 17 1972 p 81 Retrieved September 7 2022 Philips Richard April 9 1972 Sears Tower Case May Cloud More than TV Chicago Tribune p 414 Retrieved September 7 2022 a b Osbon John April 14 1972 Ghosts Walk Flak Flies Over Sears Tower TV Women s Wear Daily Vol 124 no 74 p 18 ProQuest 1523617607 a b Phillips Richard April 9 1972 Sears Tower Case May Cloud More than TV Chicago Tribune p 185 Retrieved September 7 2022 TV Antennas Studied for Sears Tower Chicago Tribune April 8 1972 p 3 Retrieved September 7 2022 Phillips Richard May 7 1972 Tower Keeps Rising Sears TV Suits Delayed Chicago Tribune p 40 Retrieved September 8 2022 Cost of Sears Move Million Per Station Chicago Tribune April 27 1972 p A13 ProQuest 170299578 Channel 7 Antenna to Be Atop Sears Tower The Daily Herald April 28 1972 p 2 Retrieved September 7 2022 Equipment amp Engineering 8 Chicago TV s reject Sears plan Broadcasting Vol 82 no 19 May 8 1972 p 54 ProQuest 1016866948 8 Channels Rap Sears TV Tower Plea Chicago Tribune April 28 1972 p 1 ProQuest 170289375 Suit Against Sears Tower TV Ghosts Is Dismissed Chicago Tribune May 18 1972 p 2 Retrieved September 7 2022 a b Yabush Donald May 25 1972 Lake County Plans to Appeal Sears Tower TV Ghosts Suit Chicago Tribune p 132 Retrieved September 7 2022 Sneed Michael June 13 1972 TV Right Denied Tower Opponents Suffer Setback Chicago Tribune p 3 Retrieved September 7 2022 TV Disruption by Sears Tower Beyond Our Jurisdiction FCC Chicago Tribune May 27 1972 p 1 Retrieved September 8 2022 Phillips Richard June 17 1972 FAA Approves TV Antennas on Sears Tower Chicago Tribune pp 1 2 Retrieved September 8 2022 FAA Approves TV Antennas for Chicago s Sears Tower The Journal Times June 17 1972 p 2 Retrieved September 8 2022 Sears TV Ghost Plea Rejected Chicago Tribune July 1 1972 p 95 Retrieved September 8 2022 Work Still Halted on Sears Tower Chicago Tribune July 11 1972 p 22 Retrieved September 8 2022 a b Engle Bryce August 15 1972 Sears Offers Cash to Aid TV Chicago Tribune p 1 ProQuest 169200463 Sears to Shoo Ghosts By Putting TV Masts Atop Its Skyscraper Work on Bases May Be Started In December for Move From Chicago John Hancock Sites The Wall Street Journal August 15 1972 p 11 ISSN 0099 9660 ProQuest 133688461 FCC Upheld on Sears Tower Chicago Tribune September 12 1972 p 3 Retrieved September 8 2022 Equipment amp Engineering Supreme Court refuses to stop Sears building Broadcasting Vol 83 no 20 November 13 1972 pp 41 42 ProQuest 1016888089 Ruling Allowing Blacks to Collect Damages For Job Bias Left Standing by High Court The Wall Street Journal November 7 1972 p 2 ISSN 0099 9660 ProQuest 133690746 a b c Sears Tower Now Tallest in Chicago Chicago Tribune November 12 1972 pp 101 102 Retrieved September 8 2022 Chicago Skyscrapers Onward and Upward The New York Times October 6 1972 ISSN 0362 4331 Retrieved September 8 2022 Sears Tower Antennas Eyed 73 Chicago Tribune November 8 1972 p 51 Retrieved September 8 2022 Sears Tower work reaches 100th floor Chicago Tribune February 24 1973 p 75 Retrieved September 8 2022 Nelson Bryce May 3 1973 Topping Out of Sears Tower Will Give Chicago the Skyscraper Lead Los Angeles Times p 20 ProQuest 157279327 Kamin 2001 p 105 a b Seek cause of Sears fire that killed 4 Chicago Tribune April 13 1973 p 74 Retrieved September 8 2022 Sears Tower Fire Kills 4 Working in Elevator Shaft The New York Times April 12 1973 ISSN 0362 4331 Retrieved September 8 2022 1 dies in Sears Tower fall 5th victim in 4 days Chicago Tribune April 15 1973 p 2 ProQuest 169276010 Strong James June 2 1973 Strike halts work at Sears Tower Chicago Tribune p 19 Retrieved August 24 2022 Total Work Stoppage Of Construction Due In Chicago Area Today The Wall Street Journal June 4 1973 p 20 ISSN 0099 9660 ProQuest 133810720 a b Oppenheim Carol September 9 1973 Offices for 7 000 employes Sears begins big move to tower this weekend Chicago Tribune p 40 Retrieved September 12 2022 BUILDING BIG Databank Sears Tower www pbs org Retrieved September 12 2022 1634 1699 McCusker J J 1997 How Much Is That in Real Money A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States Addenda et Corrigenda PDF American Antiquarian Society 1700 1799 McCusker J J 1992 How Much Is That in Real Money A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States PDF American Antiquarian Society 1800 present Federal Reserve Bank of Minneapolis Consumer Price Index estimate 1800 Retrieved April 16 2022 Sears to Shoo Ghosts By Putting TV Masts Atop Its Skyscraper Work on Bases May Be Started In December for Move From Chicago John Hancock Sites The Wall Street Journal May 22 1973 p 8 ISSN 0099 9660 ProQuest 133807447 In brief Weekend moving day to Sears Tower Women s Wear Daily Vol 127 no 50 September 11 1973 p 14 ProQuest 1627236636 Big beacons to flash atop Sears Tower Chicago Tribune September 15 1973 p 9 Retrieved September 12 2022 Local TV Radio amp Syndication Sears Tower Gives Ultimatum To Stations On Hancock Switch Variety Vol 272 no 6 September 19 1973 p 26 ProQuest 963306761 a b Two television stations to move to Sears Tower Chicago Tribune October 24 1973 p 14 Retrieved September 12 2022 a b Radio Television Tall Tower A Searing Issue As Chi TV Stations Plot Moves Variety Vol 273 no 4 December 5 1973 pp 36 42 ProQuest 1032471721 WLS TV has clearer reception from Sears Tower Chicago Defender February 4 1974 p 14 ProQuest 494041980 WTTW to begin beaming from Sears Tower Chicago Tribune March 27 1974 p 14 Retrieved September 12 2022 New Sears Tower leases listed Chicago Tribune March 18 1974 p 67 Retrieved September 12 2022 Oppenheim Carol October 26 1974 A whatchama Calder sculpture conquers the city Chicago Tribune pp 1 4 Retrieved September 12 2022 a b c d e Drexler Arthur Menges Axel 2009 SOM Architecture of Skidmore Owings amp Merrill 1963 1973 Monacelli Press p 170 ISBN 978 1 58093 221 9 Osbon John October 30 1974 Sears in process of firing 500 at Tower in Chicago Women s Wear Daily Vol 129 no 87 pp 1 22 ProQuest 1627541851 a b Sears Tower makes dramatic new entrance Chicago Tribune February 1 1984 p 31 Retrieved August 25 2022 a b c d Sears Tower world s tallest to get face lift The Dispatch February 5 1984 p 44 Retrieved August 25 2022 a b c Sears Tower is still world s tallest The Dispatch September 15 1985 p 42 Retrieved August 25 2022 Gapp Paul November 17 1985 Sears Tower s need for changes shows the dangers of thinking too big Chicago Tribune p 321 Retrieved August 25 2022 Ziemba Stanley November 6 1988 Sears executives face a towering selling job Chicago Tribune pp 1 30 Retrieved August 25 2022 Sears offering tower concessions The Dispatch April 4 1989 p 22 Retrieved August 25 2022 Ziemba Stanley June 23 1989 Sears pushing 1 billion plus bid for Tower Chicago Tribune pp 41 46 Retrieved August 25 2022 Ziemba Stanley November 5 1989 Sears faces tough sell leasing Tower office space Chicago Tribune p 135 Retrieved August 25 2022 Ziemba Stanley September 16 1989 Sears Tower sale to Olympia amp York may be dead Chicago Tribune pp 21 23 Retrieved August 25 2022 Ziemba Stanley November 16 1989 Sears Plans to Refinance Keep Tower Chicago Tribune Retrieved August 24 2022 a b c A CASE STUDY OF THE DEVELOPMENT RE FINANCINGS AND SALE OF NORTH AMERICA S TALLEST BUILDING tribunedigital chicagotribune Archived from the original PDF on November 9 2021 Retrieved February 9 2018 77 W Wacker ready to go Chicago Sun Times HighBeam Research November 2 2012 Archived from the original on November 2 2012 Retrieved September 12 2022 Willis who Sears Tower gets new name NBC News Retrieved November 10 2021 Vinocur Barry December 8 1997 A Look at the Finer Points of the Sears Tower Sale Barron s Sears Tower Headlines December 14 2001 Archived from the original on December 14 2001 Retrieved September 12 2022 Sears Tower Headlines December 14 2001 Archived from the original on December 14 2001 Retrieved September 12 2022 MetLife Selling Chicago s Sears Tower AP NEWS March 12 2004 Retrieved August 24 2022 Corfman Thomas A March 12 2004 Group to buy Sears Tower for 835 million Chicago Tribune Retrieved August 24 2022 Biz Briefs Chicago Sun Times May 1 2004 Archived from the original on October 26 2012 Retrieved September 12 2022 via HighBeam Research Biz Briefs Chicago Sun Times April 30 2004 Archived from the original on October 26 2012 Retrieved September 12 2022 via HighBeam Research Sears Tower s owners complete refinancing Crain s Chicago Business February 1 2007 Retrieved August 24 2022 Diesenhouse Susan August 12 2007 Sears Tower Tall bill to fill Chicago Tribune Retrieved August 24 2022 Roeder David October 12 2007 Tall order for Tower Sears Tower owners to press city for zoning change subsidy to add 2nd building as part of mega million dollar project next to landmark Chicago Sun Times Archived from the original on November 2 2012 Retrieved September 12 2022 via HighBeam Research Sears Tower in silver Chicago Sun Times February 25 2009 Archived February 17 2010 at the Wayback Machine Sears Tower name to change to Willis Tower Chicago Tribune March 12 2009 Archived from the original on April 19 2009 Retrieved May 1 2009 Cullotta Karen Ann March 13 2009 Illinois New Name for the Sears Tower The New York Times ISSN 0362 4331 Retrieved September 12 2022 a b c Podmolik Mary Ellen July 16 2009 Sears Tower name change Building today officially becomes Willis Tower Chicago Tribune Archived from the original on July 3 2012 Retrieved July 16 2009 Willis who Sears Tower gets new name NBC News July 16 2009 Retrieved September 12 2022 Jonas Ilaina June 1 2011 Exclusive Owners of former Sears Tower seek investor U S Retrieved August 24 2022 Willis Tower Up For Sale CBS News March 5 2015 Retrieved August 24 2022 Blackstone seals deal to buy Willis Tower Crain s Chicago Business March 15 2015 Retrieved August 24 2022 Harris Melissa March 15 2015 Willis Tower to be sold for 1 3 billion to Blackstone Group Chicago Tribune Retrieved August 24 2022 Willis Tower in line for a 500 million facelift Chicago Sun Times Retrieved October 3 2018 Willis Tower owner unveils 500 million redevelopment vision Crain s Chicago Business January 31 2017 Retrieved August 24 2022 a b c d e f Rogal Brian J May 23 2022 Willis Tower owners wrap up 500 million makeover that includes new retail hub enhanced amenities Chicago Tribune Retrieved September 7 2022 a b c d e f Gauer James May 1 2022 Willis Tower Transformation by Gensler Architectural Record Retrieved September 7 2022 a b Koziarz Jay May 8 2018 Willis Tower is getting faster greener elevators Curbed Chicago Retrieved September 7 2022 a b c Ori Ryan Brinson Jemal R May 4 2018 Willis Tower getting new elevators Here are the ups and downs Chicago Tribune Retrieved September 7 2022 Willis Tower s new loan 1 billion Crain s Chicago Business February 7 2017 Retrieved August 24 2022 Sudo Chuck April 3 2018 Blackstone Group Refinances Willis Tower Debt As Redevelopment Costs Climb Bisnow Retrieved August 24 2022 Pilgrim Lexi April 3 2018 Blackstone takes out record 1 3B refi for Willis Tower The Real Deal Chicago Retrieved August 24 2022 Blackstone piles on more debt at Willis Tower Crain s Chicago Business April 2 2018 Retrieved August 24 2022 a b Koziarz Jay April 6 2018 Willis Tower says goodbye to its lunchbox pavilion Curbed Chicago Retrieved September 7 2022 Willis Tower s Iconic Globe Sculpture Has A New Home In The Suburbs Bisnow February 15 2018 Retrieved September 7 2022 Selvam Ashok June 28 2018 Willis Tower Club Debuts a New 66th Floor Restaurant and Lounge Eater Chicago Retrieved September 7 2022 Koziarz Jay November 16 2017 Big changes on tap for Willis Tower s Metropolitan Club Curbed Chicago Retrieved September 7 2022 Willis Tower getting its first food hall Crain s Chicago Business September 6 2018 Retrieved September 7 2022 Selvam Ashok September 7 2018 A Food Hall is Coming to Willis Tower Eater Chicago Retrieved September 7 2022 Aon to Buy Willis Towers Watson Insurance Journal March 9 2020 Retrieved September 12 2022 Dummett Ben March 9 2020 Insurance Broker Aon Strikes Year s Biggest M amp A Deal on Tumultuous Markets Day The Wall Street Journal ISSN 0099 9660 Retrieved September 12 2022 Smith Ryan April 2020 Willis Tower Name Changes Ranked by Likelihood Chicago Magazine Retrieved September 12 2022 Insurance brokers Aon and Willis Towers Watson scrap their 30 billion merger CNBC July 26 2021 Retrieved September 12 2022 Willis Tower unveils 500 million makeover with updates to the Skydeck CBS News May 24 2022 Retrieved August 24 2022 Hourie Ilya May 24 2022 Blackstone Unveils 500M Renovation Of Willis Tower The Real Deal Chicago Retrieved August 24 2022 Goldstein Matthew Creswell Julie Eavis Peter April 27 2023 Stress Builds as Office Building Owners and Lenders Haggle Over Debt The New York Times Shane Scott Zarate Andrea June 24 2006 F B I Killed Plot in Talking Stage a Top Aide Says The New York Times ISSN 0362 4331 Retrieved September 12 2022 Seven charged over Chicago plot June 23 2006 Retrieved September 12 2022 Sears Tower plot trial begins October 3 2007 Retrieved September 12 2022 Five guilty in Chicago bomb plot May 12 2009 Retrieved September 12 2022 Sears Tower plot leader is jailed November 20 2009 Retrieved September 12 2022 Sears Tower to Lose Largest Tenant The Chicago 77 www thechicago77 com January 9 2009 Retrieved October 3 2018 Flooding at Willis Tower knocks TV radio signals off the air May 20 2020 Pridmore amp Larson 2018 p 181 Sears Tower CrediFi com Retrieved September 19 2016 a b c d e f g h Hoyt Monty June 22 1973 Sears Tower world s tallest may also be world s safest No alternative to safety Bundled tube design The Christian Science Monitor p 12 ProQuest 511514170 Sears Tower TallestBuildingintheWorld com September 2 2007 Archived from the original on February 26 2009 Retrieved September 14 2009 a b c Zaknic Ivan Smith Matthew Rice Dolores B Council on Tall Buildings and Urban Habitat 1998 100 of the world s tallest buildings Gingko Press p 207 ISBN 3 927258 60 1 OCLC 40110184 National Academy of Engineering 1979 Memorial Tributes National Academies ISBN 9780309034821 NAP 14723 Burj Dubai The new pinnacle of vanity Telegraph Archived from the original on January 11 2022 Retrieved February 25 2014 Top 10 world s tallest steel buildings Constructionweekonline com Retrieved February 25 2014 Alcoa to Supply Sears Tower Aluminum Sheet Chicago Tribune August 9 1971 p 68 Retrieved September 7 2022 a b The Times News February 15 1975 a b c d e f g Nagelberg Alvin June 24 1973 Going up a fantastic elevator voyage The Sears Tower Almanac 14 Sears Escalators link the 33d and 34th floors Chicago Tribune p I14 ProQuest 170442312 a b c Sears Tower Now Tallest In Nation The Washington Post Times Herald June 2 1973 p E12 ISSN 0190 8286 ProQuest 148412303 a b c Final Touches Remain for Catalog Willis Tower s New Podium in The Loop Chicago YIMBY October 22 2020 Retrieved September 7 2022 a b c d Art of the Neighborhood New Willis Tower Retrieved September 7 2022 a b c Li Jennifer S January 13 2021 Olafur Eliasson s New Chicago Art Installation Captures Shifting Sunlight and a Changing Climate Architectural Digest Retrieved September 7 2022 Neira Juliana January 20 2021 Olafur Eliasson Installs 1 963 Dynamic Metal Tiles at Chicago s Willis Tower designboom Retrieved September 7 2022 Zahour Frank January 3 1971 City Planners Consider Pioneer Ideas for Including Fire Safety in Sears Tower Chicago Tribune p 34 Retrieved September 7 2022 Nagelberg Alvin January 27 1971 Sears Tower Goes Electric Standard Turns to Gas Chicago Tribune p 53 Retrieved September 7 2022 Sears Tower betters code Chicago Tribune March 11 1973 p 551 Retrieved September 8 2022 a b c d e Sears Tower What the Pedestrian Will See Chicago Tribune October 11 1970 p C1 ProQuest 169950437 a b Nagelberg Alvin April 11 1971 Glass Elevators Give Hotel Lift Chicago Tribune p 49 Retrieved September 7 2022 Koziarz Jay July 16 2019 Cloud like sculpture of 7 000 hanging disks floats above Willis Tower lobby Curbed Chicago Retrieved September 7 2022 Fazlur Khan Sculpture SEAOI Retrieved February 25 2014 a b Selvam Ashok October 16 2019 Inside Willis Tower s 500 Million Renovation Which Includes New Restaurants and a Food Hall Eater Chicago Retrieved September 7 2022 a b Koziarz Jay October 15 2019 Checking in on Willis Tower s new retail and dining complex Curbed Chicago Retrieved September 7 2022 abc7NY One World Trade Center in New York to surpass Willis Tower in Chicago as tallest building in US ABC7 New York abc7ny com ABC7 New York Retrieved November 10 2021 Rackl Lori December 15 2019 Chicago spot makes TripAdvisor s list of world s top tourist attractions in 2019 Chicago Tribune Retrieved October 12 2021 Sears Tower unveils 103rd floor glass balconies USA Today July 1 2009 The Ledge at Skydeck Chicago Archived from the original on June 8 2011 Retrieved May 15 2011 SOM com Project Page BJ Lutz May 30 2014 Coating on Willis Tower Skydeck s Ledge Cracks Under Tourists Nbcchicago com Retrieved August 26 2014 Sophie Lewis June 12 2019 Protective layer of Willis Tower s SkyDeck cracks under visitors feet cbsnews Retrieved June 12 2019 Metz Tim March 4 1974 Where s the Highest Structure in World Well It s Not Chicago New Toronto Tower May Kill Birds and Induce Vertigo But Some Think It s Great The Wall Street Journal p 1 ISSN 0099 9660 ProQuest 133852336 CTBUH Tall Building Database Council on Tall Buildings and Urban Habitat Archived from the original on October 25 2008 Retrieved April 10 2008 a b Kamin 2001 p 109 Height The History of Measuring Tall Buildings Council on Tall Buildings and Urban Habitat Archived from the original on April 10 2012 Retrieved May 1 2012 Willis tower foundation https www mountrainierpark com taipei 101 vs sears tower With this you would actually be looking down to Taipei 101 s top floor Burj Khalifa surpasses the height of Sears Tower in Chicago Visitdubai info December 9 2007 Archived from the original on March 21 2009 Retrieved October 31 2011 Freedom Tower World Trade Center 1 NYC Tower Archived from the original on December 21 2008 Retrieved November 30 2008 Willis Tower Fun Facts Fun Facts for Children Skydeck Chicago Retrieved November 8 2020 Chicago Cubs History and News Welcome to Just One Bad Century Justonebadcentury com Archived from the original on March 20 2012 Retrieved October 31 2011 Sears Tower in Chicago Is Scaled by Stunt Man New York Times May 26 1981 Retrieved October 31 2011 Spiderman scales Sears Tower in Chicago August 20 1999 CNN Retrieved September 14 2009 Pathieu Diane November 4 2019 Hundreds of stair climbers reach new heights for annual SkyRise Chicago at Willis Tower ABC 7 Chicago Retrieved May 10 2020 Sears Tower Now Willis Chicago Tribune July 16 2009 Archived from the original on July 3 2012 Retrieved July 16 2009 Burns Greg July 16 2009 Burns on Business Willis Wants to be Part of Chicago by Way of Jersey Chicago Tribune Archived from the original on July 3 2012 Retrieved July 16 2009 Podmolik Mary Ellen 2009 Sears Tower name change has few Chicago fans Willis Tower may have trouble winning over public Chicago Tribune March 13 2009 Sears Tower Now Named Willis Tower CNN July 16 2009 Retrieved July 17 2009 Johnson Geoffrey 2010 Top 40 Buildings in Chicago Chicago October 2010 Archived from the original on December 24 2018 Retrieved October 12 2010 Suddath Claire February 8 2010 Top 10 Worst Corporate Name Changes It s the Sears Tower TIME Archived from the original on February 22 2010 Retrieved February 8 2010 Zorn Eric 2013 Change of Subject Thillens Stadium is no more Chicago Tribune June 24 2013 Archived from the original on June 22 2013 Retrieved June 23 2013 FM Query Results Audio Division FCC USA Fcc gov Retrieved September 7 2016 FM Query Results Audio Division FCC USA Fcc gov Retrieved September 7 2016 TV Query Results Video Division FCC USA Fcc gov Retrieved September 7 2016 TV Query Results Video Division FCC USA Fcc gov Retrieved September 7 2016 Filming Locations for Ferris Bueller s Day Off Movie locations com Archived from the original on April 30 2009 Retrieved September 14 2009 The Sears Tower Dressed In Sears Clothing Nbc5 com Archived from the original on March 2 2008 Retrieved October 31 2011 Keith Darce January 31 2007 Madison Avenue turns to Main Street The San Diego Union Tribune Retrieved September 14 2009 The Dark Knight helped spawn a filmmaking boom in Chicago The A V Club October 17 2013 Retrieved September 3 2022 Transformers jumpers up in birdland Chicago Tribune Retrieved September 3 2022 Merrion Paul September 7 2011 Willis Tower CBOT Building star in Superman filming ChicagoBusiness Retrieved July 26 2013 Sources Kamin Blair 2001 Why Architecture Matters Lessons from Chicago University of Chicago Press ISBN 978 0 226 42322 7 Pridmore Jay Larson George A 2018 Chicago Architecture and Design 3rd ed ABRAMS ISBN 978 1 68335 421 5 External links Wikimedia Commons has media related to Willis Tower Official website Willis Tower office space leasing website Willis Tower Skydeck website Willis Tower on CTBUH Skyscraper Center Willis Tower Emporis Archived from the original on September 23 2015 Willis Tower at StructuraeRecordsPreceded byOne World Trade Center 1970 Tallest building in the world1 450 ft1973 1998 Succeeded byPetronas TowersWorld s tallest building architectural element1 450 ft1973 1998Building with the most floors108 floors2001 2007 Succeeded byBurj KhalifaWorld s tallest building rooftop1 450 ft1973 2003 Succeeded byTaipei 101Tallest building in the United States1 450 ft1973 2013 Succeeded byOne World Trade Center 2006 Preceded byAon Center Tallest building in Chicago1 450 ft1973 present Incumbent Retrieved from https en 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