The Gateway Arch

A 630-foot catenary arch of stainless steel, as wide between its legs at the ground as it is tall, rising from the riverfront grounds above the Mississippi. Each leg is an equilateral triangle in section, tapering from 54 feet on a side at the base to 17 feet at the top, so the curve thins as it climbs. The polished skin carries no ornament or visible joints from a distance, and a row of small observation windows lines the top of the span.

The Jefferson National Expansion Memorial was established in 1935 to commemorate St. Louis's role in the nation's westward expansion, and some forty blocks of the old riverfront were cleared for it between 1939 and 1942. Eero Saarinen won the memorial's design competition in 1948 with a stainless-steel arch. Construction began in February 1963, two years after Saarinen's death, and the final section was set at the top on October 28, 1965. Trams inside the legs began carrying visitors to the observation deck in 1967. The grounds, museum, and approaches were rebuilt in the CityArchRiver project, and in 2018 the memorial was renamed Gateway Arch National Park.