From 1973 to 1998, the Sears Tower was the world's tallest building. The tower reaches 1450 feet to the roof, and 1730 feet to the top of it's antennae. With 110 floors, The Sears Tower has the second most total floor space of any building in the United States, only behind The Pentagon.
The Sears Tower Skydeck observation deck opened on June 22, 1974 and is located on the 103rd floor of the tower. It takes about 45 seconds to soar to the top in either of two special elevators. The bathrooms on the Skydeck are the highest in the world.