The Gateway Arch in St. Louis Missouri designed by Eero Saarinen stands at 630 feet tall making it the tallest arch in the world. It is made up of stainless steel and modeled after a weighted catenary arch. The arch also stands as Missouri’s tallest accessible building. A very beautiful monument to westward expansion in the United States and has become the symbol for St. Louis and a very popular tourist attraction with its breath taking size and sleek design.