In 1935 the St. Louis riverfront was selected as the site for construction of a monument to commemorate the westward expansion of the United States in the 19th century. An area of 40 city blocks was purchased and all buildings were cleared, but because of World War II, progress on the Memorial was halted.
In 1947 the Jefferson National Expansion Memorial Association, a group of public-spirited citizens, held a nationwide competition to obtain an appropriate design for the Memorial. The winner in the competition was architect Eero Saarinen whose idea of a giant stainless steel arch in the shape of an inverted catenary curve is a complex engineering feat. In 1963, construction began on The Arch and was completed in 1965.
Source: St. Louis Convention and Visitors Commission