St. Louis' Gateway ArchDuring the 19th century St. Louis, Missouri, was the largest city on the edge of the western frontier. To honor those early pioneers, city leaders agreed to build a monument that would become the iconic landmark for the St. Louis skyline. After a national competition that started in 1947, Finnish-American architect Eero Saarinen’s design came in first place. He broke ground on building his freestanding, stainless steel arch in 1963. What became the tallest man-made monument in the U.S. was completed October 28, 1965. The “Gateway Arch” opened to the public June 1967.