willis tower

Formerly known as the Sears Tower, the Willis Tower is a 444.3 meter (1,451-foot) tall skyscraper located in the Loop area of Chicago, Illinois, the United States. The skyscraper was built from 1970 to 1974, and held the title of tallest building from 1973 to 1998, when it was surpassed by the Petronas Twin Towers.