Willis Tower
| Willis Tower | |
|---|---|
Willis Tower as seen from Lake Michigan in April 2019 | |
| Former names | Sears Tower (1973–2009) |
| Record height | |
| Tallest in the world from 1973 to 1998[I] | |
| Preceded by | World Trade Center |
| Surpassed by | Petronas Towers |
| General information | |
| Status | Completed |
| Type | Office, observation, communication |
| Architectural style | International |
| Location | 233 S. Wacker Drive Chicago, Illinois 60606 United States |
| Coordinates | 41°52′44″N 87°38′09″W / 41.8789°N 87.6358°W |
| Current tenants | |
| Named for | Willis Towers Watson Sears (1973–2009) |
| Construction started | 1970 |
| Completed | 1974 |
| Opening | September 1973 |
| Cost | US$150 million |
| Owner | Blackstone Group |
| Height | |
| Architectural | 1,451 ft (442 m) |
| Tip | 1,707 ft (520.3 m) after antennas added in 1982, 1,729 ft (527.0 m) after antenna extension in 2000 |
| Top floor | 1,354 ft (413 m) |
| Technical details | |
| Floor count | 110 (+3 basement floors) |
| Floor area | 4,477,800 sq ft (416,000 m2) |
| Lifts/elevators | 104, with 16 double-decker elevators, made by Westinghouse, modernized by Schindler Group and recently modernized by Otis Elevator Company |
| Design and construction | |
| Architect(s) | Skidmore, Owings & Merrill Fazlur Rahman Khan Bruce Graham |
| Engineer | Jaros, Baum & Bolles (MEP), Aon Fire Protection Engineering, formerly Schirmer Engineering Corporation (Fire) |
| Structural engineer | Skidmore, Owings & Merrill |
| Main contractor | Morse Diesel International |
| References | |
| I. ^ "Willis Tower". Emporis. Archived from the original on September 23, 2015. | |
The Willis Tower, formerly and still commonly referred to as 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.
The building occupies a site bound 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. 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. As of April 2018, the building's largest tenant is United Airlines, which occupies around 20 floors. Other major tenants include the building's namesake Willis Towers Watson, and law firms Schiff Hardin and Seyfarth Shaw. Morgan Stanley became the building's fourth-largest tenant in 2017.