Willis Tower’s was designed by architectural firm Skidmore, Owings and Merrill.

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2,000 construction workers took part in building Willis Tower.

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The building features a steel-framed bundled-tube construction method.

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Willis Tower was the world’s tallest building until 1998.

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12th tallest building in the world.

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1,450 feet high (443 meters) and 110 stories tall.

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Combined weight of the building is 222,500 tons.

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104 elevators moving 1,200 feet per minute.

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The structure was completed in May 1973

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As part of the building's recycling program, tenants recently recycled over 2,103 tons of paper, aluminum, glass, & plastic and construction waste annually.

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