On this day in 1965, the keystone of the Gateway Arch was about to be slipped into place — a moment that was years in the making. The monumental arch, designed by Finnish architect Eero Saarinen, required 142 separate pieces in the shape of equilateral triangles to form its graceful, awe-inspiring shape. After six years of construction, everything was riding on the last piece. If the two legs were even an inch out of sync, the entire 630-foot structure was doomed. As the crane slowly descended, St. Louis held its breath as the last steel triangle fit perfectly. The largest monument in the U.S. — and the largest human-made arch in the world — was complete.
A major transportation hub situated at the confluence of the Mississippi and Missouri rivers, St. Louis served as the starting point for many daring treks west during the 19th century. The museum at the Gateway Arch explores both the benefits and costs of America’s Westward Expansion, which extended the nation’s borders while displacing tens of thousands of Indigenous peoples. Today the arch stands as a monument to everyone impacted by this era, which shaped the nation as we know it today.
