The Ledge is a glass box on the 103rd floor of the Willis Tower, the eighth-tallest building in the world and the tallest building in the Western hemisphere. At an altitude of 1,353 feet you can ...

Chicago is home to one of the tallest buildings in the world: the Willis Tower. So tall that on a windy day, the topmost floors can sway as much as three feet. But what keeps it from falling?