Willis Tower

Standing tall above every other skyscraper in Chicago, Willis Tower (formerly known as the Sears Tower) is a 110-story building in the heart of downtown.

One of the tallest buildings in the world and the tallest building in America, it is impossible to miss when appreciating the skyline.

In 1969, Sears Roebuck and Company was the largest retailer in the world, with about 350,000 employees. Deciding it needed a central office space for its many employees, the company hired architects Skidmore, Owings and Merrill to design what would become one of the largest office buildings in the world. After breaking ground in 1970, it took three years to complete and used enough concrete to make an eight-lane, five-mile-long highway. The last beam put in place was commemorated by the signatures of 12,000 construction workers, Sears employees, and Chicagoans.

In 1988, Sears Roebuck and Company sold and moved out of the building, but the Sears Tower name remained the same. It was renamed Willis Tower in 2009 after the Willis Group Holdings, the global insurance broker who calls the Tower its Midwest home.

In July 2009, U.S. Equities led the design and construction of a multi-million dollar renovation of Skydeck Chicago, including the development of The Ledge, a series of glass bays on the 103rd floor that extend from the building providing visitors with unobstructed views of Chicago through the windows and glass floors – 1,353 feet straight down. In addition to The Ledge, the new Skydeck visitor center features museum-quality interactive exhibits. The opening of The Ledge has provided the Skydeck with record-breaking visitor counts consistently since its debut.

In May 2011, Skydeck Chicago opened Skydeck Marketplace, a brand new, 7,500 square foot retail and express cafe experience.  Visitors can purchase their choice of over 300 unique Chicago, Ledge and Willis Tower items and are treated to authentic Chicago food and beverages including Connie's Pizza, Eli's Cheesecake and Vienna Hot Dogs.


Willis Tower has been part of the Chicago skyline for decades so it’s easy to overlook the true magnitude of this magnificent steel frame skyscraper. Take a look at these facts and figures and we guarantee you won’t look at America's tallest building the same way again.

Property Size and Details:

  • Willis Tower contains approximately 4.56 million gross square feet and has a rentable area of 3.8 million square feet.
  • 4.56 million gross square feet would cover 105 acres if spread across one level, or the equivalent of 16 city blocks in Chicago.
  • Within the building, there are 25 miles of plumbing, 1,500 miles of electric wiring, 80 miles of elevator cable, and 145,000 light fixtures.
  • The building weighs more than 222,500 tons, and it cost more than $175 million to build.
  • Each floor of the building is divided into 75-foot, column-free squares, or “mega-modules,” which provide maximum planning, flexibility and efficiency.
  • Large windows provide maximum light and views, further enhanced by the corridors created by the tower’s set back on all sides.
  • Only the finest materials are used throughout the buildings common areas to highlight the property’s prestige, such as the lobby’s walls of travertine highlighted with stainless steel trim, polished granite flooring, and decorative ceiling lighting.

Willis Tower Fun Facts

History and Facts