Gateway Arch National Park , in St. Louis, Missouri, is the site of the Gateway Arch, the tallest monument in the United States. The arch, wrapped in stainless steel, rises 630 feet (192 meters) above downtown St. Louis, on the Mississippi River. The popular tourist attraction was built to commemorate the nation’s westward expansion during the 1800’s. Visitors may take trams up either leg of the arch to an observation room at the top. The Gateway Arch National Park (formerly the Jefferson National Expansion Memorial) also includes an underground visitor center, theater, and museum.
From leg to leg at its base, the arch measures 630 feet (192 meters) wide. It is made of 142 stacked triangular sections of double-walled steel, reinforced with concrete at its lower levels. From the base to the top, the legs taper from 54 to 17 feet (16.5 to 5.2 meters) wide.
In 1948, the Finnish-born American architect Eero Saarinen won a national competition to design the memorial. His design calls to mind the steel arches of the nearby Eads Bridge, the first bridge to cross the Mississippi River at St. Louis. Saarinen died in 1961, before construction began on his project. Work on the monument began in 1963 and was completed in 1965. The monument opened to the public in 1967.
St. Louis was chosen as the site of the memorial because of the city’s role as a “gateway” in the nation’s expansion westward. In 1803, the U.S. government purchased from France a huge area that lay between the Mississippi River and the Rocky Mountains (see Louisiana Purchase ). United States Army officers Meriwether Lewis and William Clark were selected to explore this area. In May 1804, a camp near St. Louis was the starting point for their expedition.
