Chicago Architecture Info

The Willis Tower

Formerly known as The Sears Tower
The Sears Building
233 South Wacker Drive
Chicago, Illinois 60606
Photograph © Wayne Lorentz
Basic Information
Designed by Skidmore, Owings & Merrill
Cost $186,000,000
Type Skyscraper
Floors: 110
Maximum length 195 feet/59 meters
Neighborhood: The Loop
More Information
  • Height to tip of west antenna: 1,729 feet
  • Height to tip of east antenna: 1,709 feet
  • Height to roof: 1,450 feet, seven inches
  • Height to glass ledges: 1,353 feet
  • Official stories: 110
  • Missing floor: 109. The building owners count the roof as 109.
  • Disputed floor: The mechanical penthouse for the elevators. Some buildings count this, some do not. Sears Tower does.
  • Total floor space: 4,560,000 square feet
  • Rentable floor space: 3,800,000 square feet
  • Weight: 222,500 tons / 445,000,000 pounds
  • Caissons: 114 in bedrock 65 feet underground
  • Elevators: 104
  • Double-decker elevators: 14
  • Escalators: 15
  • Observatory elevators speed: 18.2 miles per hour
  • Windows: 16,100+
  • Property size: 2.96 acres
  • Parking spaces: 160
  • Plumbing: 25+ miles
  • Electrical: 1,500+ miles
  • Elevator cables: 80+miles
  • Architect: Bruce Graham
  • Structural engineer: Fazlur R. Khan
  • Bounding streets: Upper South Wacker Drive, Lower South Wacker Drive, West Jackson Boulevard, South Franklin Street, West Adams Street.
  • West Quincy Street was removed to make way for this tower. The developers purchased it from the City of Chicago for $2,767,500.
  • The original plan for this building was just 70-stories tall.
  • Before construction, models of the this tower with the rest of the city were built and tested in a wind tunnel at the University of Western Ontario.
  • The last steel beam put into place in the construction of this building on the 110th floor was signed by over 12,000 Chicagoans.
  • The building, itself, does not have a tunes mass dampener, which is common on large skyscrapers. But both of the two large antenna masts has one of its own near the top.
  • The building's exterior is black anodized aluminum. The windows are tinted bronze.
  • According to the Chicago Sun-Times, in 2005 a deal was in the works for CDW to move to this building, which included naming rights. The deal fell apart because the building's owners didn't want the word "Discount" on the tower.
  • The building has an average sway of six inches off center.
  • April 6, 1973: Two women were hit by pieces of falling wood that broke loose from construction work on the 108th floor.
  • May 3, 1973: Topping out.
  • May 3, 1973: This building became the tallest building in the world, a title it would retain for 25 years.
  • May, 1973: This building opened to the public.
  • 1974: Construction ended.
  • 1974: The Sears Skydeck opened to the public.
  • 1981: Dan Goodwin climbed the exterior of this building.
  • 1989: This building was sold for $800,000,000 to AEW.
  • 1992: Sears moved out of this building to the suburbs.
  • 1997: This building was sold for $804,000,000 to TrizecHahn.
  • December, 1998: This building illuminated its antennae in Christmas colors for the first time.
  • 1999: Alain Robert climbed the exterior of this building.
  • September 11, 2001: The Sears Skydeck was closed after terrorists attack the World Trade Center and the Pentagon.
  • October 29, 2001: The Sears Skydeck reopened.
  • August, 2003: Trizec Properties surrendered the building to MetLife.
  • 2003: Ownership of this building was transferred to MetLife.
  • 2003: Sears' naming rights to this building expired. There was no company willing to buy the rights immediately, so the name remained Sears Tower.
  • March, 2004: This building was sold for $835 million to Jeffrey Feil and Joseph Chetrit by MetLife.
  • January 15, 2004: The <i>Chicago Tribune</i> reported that the Sears Tower would be equipped with cellular repeaters. This was to help cell phone users who have a hard time making and receiving calls in the tower because of its structure, and the fact that cell phone users inside the building can be a thousand feet higher than the nearest cell phone tower.
  • March 11, 2004: Jeffrey Feil and Joseph Chetrit purchased the Sears Tower for $835,000,000.00.
  • September 25, 2005: An investigation by Emporis determined the actual correct height to the main roof of this building is 1450 feet, seven inches.
  • 22 February, 2006: Rogue skyscraper climber Alain Robert tells <i>Vancouver 24 Hrs</i> that the Sears Tower was his favorite illegal climb.
  • May 23, 2006: A group of seven people were arrested in Miami for allegedly plotting to launch a terrorist attack on this building.
  • January 19, 2007: This building was sold for $385,000,000.
  • February 1, 2008: Several women walking by this building were shocked by electrical currents from the sidewalk. The stray voltage leaked from the system which automatically de-ices the sidewalk when it snows (a common device for large buildings in cold climates). The system was turned off until it could be determined what the problem was.
  • March 11, 2009: The Wall Street Journal reported that if insurance giant The Willis Group consolidates its offices in this building it would be renamed The Willis Tower.
  • March 12, 2009: The Willis Group announced it will move nearly 500 employees to the Sears Tower and rename it Willis Tower. It did not pay extra for the naming rights.
  • April 21, 2009: The Sears Tower signs on this building were temporarily covered by by Willis Tower banners as executives tried to figure out how many signs to hang, and where.
  • May 1, 2009: A plan was announced to add a glass floored outdoor viewing gallery to the observation level.
  • June 24, 2009: A plan was announced to give this building a $350,000,000 environmental facelift. The plan included the possibility wind turbines and greenery on the roofs, replacing all of the building's windows, and changes to the building's mechanical systems to make them more energy efficient. The goal was to reduce the building's energy use by 80%. However, earlier thoughts about painting the building silver were thrown out.
  • July 1 2009: Based on new signage, this building became The Willis Tower. The Sears Skydeck was renamed Skydeck Chicago.
  • July 2, 2009: The outdoor viewing platforms on the 103rd floor open to the public. Collectively they are called "The Ledge"
  • July 16, 2009: In a ceremony, the building name officially changed from Sears Tower to Willis Tower.
  • September, 2010: This building was named #10 on Chicago Magazine's list of the Top 40 Buildings in Chicago.