The Space Needle is an observation tower in Seattle, Washington, a landmark of the Pacific Northwest, and an icon of Seattle. It was built in the Seattle Center for the 1962 World's Fair, which drew over 2.3 million visitors, when nearly 20,000 people a day used its elevators. Once the tallest structure west of the Mississippi River, it is 605 ft (184 m) high, 138 ft (42 m) wide, and weighs 9,550 tons. It is built to withstand winds of up to 200 miles per hour (89 m/s) and earthquakes of up to 9.1 magnitude, as strong as the 1700 Cascadia earthquake. It also has 25 lightning rods. It has an observation deck at 520 ft (160 m) and the rotating SkyCity restaurant at 500 ft (150 m). The downtown Seattle skyline, as well as the Olympic and Cascade Mountains, Mount Rainier, Mount Baker, Elliott Bay and surrounding islands can be viewed from the top of the Needle. Photographs of the Seattle skyline often show the Space Needle prominently, above skyscrapers and Mount Rainier. The architecture of the Space Needle is the result of a compromise between the designs of two men, Edward E. Carlson and John Graham, Jr. The two leading ideas for the World Fair involved businessman Edward E. Carlson's sketch of a giant balloon tethered to the ground (see the gently sloping base) and architect John Graham's concept of a flying saucer (see the halo that houses the restaurant and observation deck). Victor Steinbrueck introduced the hourglass profile of the tower.