Saint Louis Arch

The Arch, designed by Finnish-American architect Eero Saarinen and structural engineer Hannskarl Bandel, stands 630 feet (192 m) tall, and is 630 feet (192 m) at its widest point. It is the tallest habitable structure in St. Louis (taller than One Metropolitan Square, the tallest building), and the second tallest in Missouri (behind One Kansas City Place in Kansas City). The cross-sections of its legs are equilateral triangles, narrowing from 54 feet (16.5 m) at the base to 17 feet (5.2 m) at the top. Each wall consists of a stainless steel skin covering reinforced concrete from ground level to 300 feet (91 m) or carbon steel and rebar from 300 feet (91 m) to the peak. The interior of the Arch is hollow and contains a unique transport system leading to an observation deck at the top. The interior of the Arch also contains two emergency stairwells of 1076 steps each, in the event of a need to evacuate the Arch or if a problem develops with the tram system. Underneath the Arch is a visitor center, entered from a descending outdoor ramp starting at either base. Within the center is the Museum of Westward Expansion, exhibits on the history of the St. Louis riverfront, and tram loading and unloading areas. Tucker Theater, finished in 1968 and renovated 30 years later, has about 285 seats and shows a documentary (Monument to the Dream) on the Arch's construction. Odyssey Theater was completed in 1993 and has 255 seats. It was the first 70 mm film theater to be located on National Park Service grounds and operated by the NPS. It runs films from a rotating play list. Also located in the visitor center are retail operations ran by the Jefferson National Parks Association, a not-for-profit partner.
Visitors pass through security checkpoints at each entrance to the Arch, before being allowed access to the visitor center. Security was increased as result of a 1997 Congressional mandate to establish a Counter-Terrorism Program at the park. The NPS used the increased funding to purchase magnetometers and x-ray equipment for visitor screening and 25 CCTV cameras scattered throughout the grounds of the memorial.