Willis Tower
The Willis Tower observation deck is called the Skydeck. It opened on June 22, 1974. It is on the 103rd floor. It is the highest observation deck in the United States and one of Chicago's most famous tourist attractions. About 1.7 million tourists visit the tower every year. Elevators reach the top of the building in about 60 seconds. People can feel the air pressure change as they go up.  The tourist entrance is on the south side of the building on Jackson Boulevard. A second observation deck on the 99th floor was made as a backup and for private events.