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 Realty 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 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.

  • Completed construction in 1973
  • 110 stories
  • Designed by architectural firm Skidmore, Owings & Merrill
  • 1,450 feet high (443 meters); 1,730 feet high (520 meters) including twin antennae
  • Eighth-tallest building in the world; tallest in Western Hemisphere
  • World’s tallest building until 1998
  • 1,354 feet to the Skydeck
  • You can see four states: Illinois, Indiana, Wisconsin and Michigan
  • 4.5 million gross square feet (418,064 gross square meters) of floor space, roughly 101 football fields
  • 3.8 million rentable square feet
  • Weighs 222,500 tons
  • 76,000 tons of steel
  • Steel-framed bundled-tube construction method
  • Average six inch (152 millimeter) building sway from true center; designed to withstand up of to three feet
  • Approximately 25,000 daily visitors
  • Accommodates more than 12,000 occupants
  • Took 2,000 workers three years to build
  • Approximately 16,100 windows
  • 25,000 miles of electrical cable
  • 43,000 miles of telephone cable
  • Cost more than $175 million to build
  • 104 elevators moving 1,200 feet per minute
  • More than 16,000 square feet of conference rooms
  • 99th floor event space
  • Two entrances
  • Broadcasting radio and television stations from the rooftop


  • 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.


At Willis Tower, we are continuously expanding our eco-conscious efforts and investigating harnessing solar energy, constructing additional green roof space, and more. Believe sustainability matters? We do, too. We have already cut the building’s original energy consumption by a third.

Who knew that the true color of the Willis Tower was green? The Willis Tower is not only an innovator in promoting green practices among its tenants, but also stands as a leader among American skyscrapers in increasing energy and water efficiency and reducing waste.

Over the past 20 years, the Tower has reduced annual electricity consumption by 34% by installing enhanced lighting systems and controls and adopting special conservation practices. The building saves 10 million gallons of water each year, or the equivalent of 156,448 full bathtubs, by relying on reduced water-flow fixtures. These innovations are spurring the building to look into certification as a LEED (Leader in Energy and Environmental Design) certified building and explore renewable energy resources, such as solar and wind power and even “green roofs” covered with vegetation. Can you imagine a thriving garden high in the sky?

Willis Tower has accomplished the following in the greening of the tallest building in the Western Hemisphere:

  • Reduced annual electricity consumption by 34 percent in the last 20 years. 
  • As part of the building's recycling program, tenants recently recycled over 2,103 tons of paper, aluminum, glass, & plastic and construction waste annually.
  • Saving more than 10 million gallons of water annually, the equivalent of 156,448 bathtubs.   
  • Recycled more than 16 tons of electronics over one year.
  • Implemented tenant bike riding programs that provide indoor bicycle parking, showers, changing rooms, complimentary loaner bikes, helmets and locks.
  • Offered parking discount incentives to tenants driving hybrid vehicles. 
  • Reduced water consumption by installing low-flow fixtures.
  • Initiated a window replacement program to improve insulation.
  • Improved energy efficiency through enhanced lighting systems and ontrols, higher efficiency motors and management practices.
  • Implemented green cleaning and maintenance programs that reduce the use of harmful chemicals.
  • Transitioned to a team cleaning approach; new staffing procedure will reduce the amount of lights on at night for energy savings

Willis Tower has also has earned the U.S. Environmental Protection Agency’s (EPA’s) ENERGY STAR certification, which signifies that the building performs in the top 25 percent of similar facilities nationwide for energy efficiency and meets strict energy efficiency performance levels set by the EPA. The Willis Tower will be the largest office building ever to receive ENERGY STAR certification, and the third-largest building overall.



There is a lot of great stuff for kids to see and do. Follow the links below to explore the various activities offered on the site for kids. Don’t forget to download them all before you come on your visit!

Skydeck Chicago’s Teacher’s Guide has 37 pages of facts and fun. Take a look!

Printable fun fact sheet, quizzes, coloring pages and even a scavenger hunt for your visit are only a click away.