The Gateway Arch is a 630-foot-tall (192 m) monument in St. Louis, Missouri. Clad in stainless steel and built in the form of a weighted catenary arch, it is the world’s tallest arch and Missouri’s tallest accessible building. Some sources consider it the tallest human-made monument in the Western Hemisphere.  Built as a monument to the westward expansion of the United States and officially dedicated to “the American people”, the Arch, commonly referred to as “The Gateway to the West”, is a National Historic Landmark in Gateway Arch Nation Park and has become an internationally recognized symbol of St. Louis, as well as a popular tourist destination. From Wikipedia

Eads designed and built the first road and rail bridge to cross the Mississippi River at St. Louis. The Eads Bridge, constructed from 1867 through 1874, was the first bridge of a significant size with steel as its primary material, and it was the longest arch bridge in the world when completed.