The Willis Tower, formerly known as the Sears Tower, is a 108-story skyscraper in Chicago, Illinois, United States.
The Willis Tower is 442 meters (1,450 feet) high – 520 meters (1,730 feet) including twin antenna towers.
At completion in 1973, it surpassed the World Trade Center towers in New York to become the tallest building in the world, a title it held for nearly 25 years; it was surpassed by the Petronas Twin Towers in 1996.
Today, it is the second-tallest building in the United States and the 14th-tallest in the world.
With 416,000 square meters (4,477,786 square feet) of space, the building is comparatively large for its height, with its foundation and the first 50 floors taking up an entire city block before the building begins to narrow.
Commissioned by Sears, Roebuck & Company, it was designed by the chief architect Bruce Graham and structural engineer Fazlur Khan of Skidmore, Owings & Merrill, SOM.
The design was inspired by an advertisement for a package of cigarettes.
It took 2,000 workers and 3 years of construction to make it into the iconic structure that it is today.
Construction began in August 1970 and was completed in May 1973.
The Sears Tower was actually constructed as a collection of nine separate buildings, planted together in a unifying square. The “tubes” share a uniform width, measuring to 23 meters (75 feet) square, but are diverse in height. Two (the northwest and southeast tubes) ascend to the building’s 50th story; two (northeast and southwest) to its 66th; three (north, south, and east) to its 90th; and two (west and center) to the Sears Tower’s peak on the 108th story.
The construction cost about US$150 million at the time, equivalent to US$800 million in 2016.
The combined weight of the building is 201,848 tonnes (222,500 US tons) – that’s 445,000,000 pounds, 201,849,000 kilograms, or almost 20,000 city buses!
Within the building, there are 40 kilometers (25 miles) of plumbing, 2,400 kilometers (1,500 miles) of electric wiring, 130 kilometers (80 miles) of elevator cable, and 145,000 light fixtures.
The Willis Tower has approximately 16,100 bronze-tinted windows.
The Willis Tower has 104 elevator with 16 double-decker elevator
The Willis Tower elevators operate as fast as 1,600 feet (488 meters) per minute – among the fastest in the world.
The Willis Tower observation deck, called the Skydeck, opened on June 22, 1974. Located on the 103rd floor of the tower, it is 1,353 feet (412 meters) high. More than one million people visit the Skydeck each year, making it one of Chicago’s most popular tourist destinations.
On a clear day, you can see four states: Illinois, Indiana, Wisconsin and Michigan. Visibility from the Skydeck is approximately 40-50 miles (65-80 kilometers).
Until July 16, 2009, the building was called Sears Tower. It was renamed after the Willis Group bought it.
For a brief period in 2009, the building entertained a makeover to accompany its rebranding as the Willis Tower. Owners considered swapping its black façade for a silver veneer but quickly decided that the Chicago landmark should only undergo one change at a time.
The Franklin Street entrance is the point from which all building heights are measured.
The lowest level of Willis Tower is 13 meters (43 feet) below the Franklin Street entrance.
The restrooms on the 103rd floor, at 412 meters (1,353 feet) high, are the highest (relative to street level) in the Western Hemisphere.
The building leans about 10 centimeters (4 inches) towards the west due to its slightly asymmetrical design, placing unequal loads on its foundation.
6 roof-mounted robotic window washing machines clean all 16,100 windows.
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 Sears Tower.
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.
The building has appeared in numerous films and television shows set in Chicago. Late Night with Conan O’Brien, Monk, Kenan and Kel, Stargate SG-1 — these are just a few of the TV shows that the tower’s been featured in. The Willis Tower was also appeared in Ferris Bueller’s Day Off, I-Robot, Man of Steel, Divergent, and many other movies.has appeared
Many broadcast station transmitters are located at the top of Willis Tower.