The Willis Tower in Chicago is the tallest building in the western hemisphere.
In 1973, the then tallest building in the world opened its doors. At 1,454 feet tall (110 stories), the Sears Tower took three years to build and more than $150 million. Although it is still commonly known as the Sears Tower, it was renamed the Willis Tower in 2009 after Willis Group Holdings leased a large part of the building. From the Skydeck, on a clear day, you can see four states - Illinois, Indiana, Wisconsin, and Michigan. The building contains enough steel to build 50,000 cars and enough telephone wiring to wrap around the world 1.75 times! And how do they keep the over 16,000 windows clean? There are six roof-mounted window washing machines.
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