Based on the Stuttgart Tower, in Germany, the Space Needle was architecturally daring at the time it was built. From the ground level to the top of the needle, the steel tower is 605 feet tall, with an Observation Deck at 520 feet. On top of the slender tripod design, the observation deck and revolving restaurant turn 360 degrees every hour. Built as a focal point for the Century 21 Exposition at the 1962 Seattle World's Fair, approximately 20,000 people a day visited the top of the Needle, for a total of 2.3 million visitors throughout the event. The Needle is the number one tourist attraction in the Northwest.