On May 25, 1948, the United States Territorial Expansion Memorial Commission formally endorsed Eero Saarinen’s sweeping stainless‑steel design for a monument rising above the Mississippi River in St. Louis. Saarinen died in 1961 and never saw his masterwork completed. Exactly twenty years after the design’s approval, on May 25, 1968, Vice President Hubert Humphrey dedicated the Gateway Arch — now the tallest man‑made monument in the United States.