The official name for the whole project = Jefferson National Expansion Memorial and it consists of the Gateway Arch, the Museum of Westward Expansion, and St. Louis' Old Courthouse.
During a nationwide competition in 1947-48, architect Eero Saarinen's inspired design for a 630-foot stainless steel arch was chosen as a perfect monument to the spirit of the western pioneers. Construction of the Arch began in 1963 and was completed on October 28, 1965.
The Arch has foundations sunken 60 feet into the ground, and is built to withstand earthquakes and high winds. It sways up to one inch in a 20 mph wind, and is built to sway up to 18 inches.