25 Interesting Facts About the St. Louis Gateway Arch

 1.) In 1935, the St. Louis Riverfront was chosen for a national monument in honor of the westward expansion of the United States. Buildings were cleared on 40 city blocks to begin the memorial; however the progression ceased due to World War I.

 2.) The Jefferson National Expansion Memorial Association held an architectural competition in 1947 for the design of the memorial.

 3.) Finland born architect Eero Saarinen won the contest with his design of a catenary curved arch. A catenary curve hangs freely from two fixed points and is flexible but it will not stretch.

 4.) Construction on the arch began on February 12, 1963 and the completion date was October 28, 1965.

 5.) The arch stands 630 feet tall and is 630 feet wide at the base, which makes it the tallest man-made monument in the United States.

 6.) The arch is made out of 886 tons of stainless steel.

 7.) The weight of the concrete in the arch totals 38,107 tons.

 8.) The arch has 142 triangular sections positioned on top of one another and welded on the inside and outside.

 9.) The arch is 63 stories tall and each story is 10 feet.

10.) Each leg is 54 feet long at the bottom and the sections taper to 17 feet at the very top.

11.) To place the last four-foot piece at the top of the arch, the legs were jacked apart with more than 500 tons of pressure.

12.) Under normal weather conditions, the arch will not sway. The wind has to blow 50 miles per hour for the top of the arch to move 1 1/2 inches from the center. The design of the arch allows for an 18 inch sway and to withstand an earthquake.

13.) There are six 1/2 by 20 inch lightning rods plus an aircraft light on the top of the arch.

14.) The cost to build the arch totaled 13 million dollars.

14.) Dick Bowser created the tram system that carries visitors to the top of the arch. He developed this system in just two weeks.

15.) After the first tram was completed, the arch opened to the public on June 10, 1967.

16.) Each leg of the arch has one tram with 8 capsules that hold 5 passengers each.

17.) The tram runs at a speed of 340 feet per minute and it takes approximately 4 minutes to get up to the top of the arch.

18.) The tram system can make as many as 80 trips each day and during the off-season in the winter, the trams make 48 trips to the top each day. At full capacity the trams carry 200 to 225 passengers every hour.

19.) There are 1076 steps in the arch; however these steps are not accessible to the public. The steps are only used for emergencies and maintenance. There are also two emergency elevators in the arch.

20.) The tram works like an elevator and a ferris wheel combined. Each capsule measures five foot in diameter and is shaped like a barrel. Each capsule has an opening in the front and a closed back. The back of each capsule is constructed with a center pivot shaft and a frame with rollers encircles the open front. The frame has wheels that run in tracks and the capsule rotates along the frame. The weight of the passengers assists in keeping the capsule upright.

21.) While traveling to the top of the arch, each capsule rotates about 155 degrees. The frame pivots around the capsule and at the loading area the tracks are above the capsule. When the capsule reaches the top of the arch, the tracks are below the capsule.

22.) The observation area measures 65 feet long by 7 feet 2 inches across by 6 feet 9 inches high. The observation area holds up to 160 people at a time.

23.) There are 16 windows on each side of the observation area. While looking out the windows on the east side, visitors can view the Mississippi River and the state of Illinois. If looking out the windows on the west side, visitors can see the city of St. Louis.

24.) Each hinged and locked window measures 7 inches by 27 inches. The windows are made out of 3/4 inch plate glass.

25.) In the observation area, visitors can see up to 30 miles when weather permits and the sky is clear.