Gateway Arch, also known as the Gateway to the West, is a well known structure the United States' tallest man-made monument. It is also the centerpiece of Jefferson National Expansion Memorial, as well as one of the tallest accessible buildings in Missouri. Designed in 1947, but only constructed in 1963 and finished in 1965, it was opened to the general public in July 10, 1967.

The Gateway Arch measures 630 feet, or 192 meters, in both height and width. It is earthquake and wind resistant, allowing it to be a very sturdy structure. It also has mathematical elements in its design.

The Gateway Arch is generally constructed in commemoration and celebration of the founding off St. Louis. Today, it is in the list of most visited attractions in the world.