Willis Tower looks like a skyscraper built by Sears at his own expense. The 442-meter-high building is 527 meters tall, the world's tallest building from 1973 to 1998. The Skydeck viewing platform on the top can see the whole city and the highest building in the United States. It's supposed to calm down in the 103-storey transparent glass Skydeck. You need no heightphobia. Believe it, you can jump and haw.