How much taller is the Gateway Arch in St. Louis than it is wide?
Despite the optical illusion, the Gateway Arch is exactly as wide (630 feet) as it is tall. It is the tallest man-made monument in the United States, and the tallest accessible structure in the state of Missouri. It is also the largest architectural structure designed as a weighted or flattened catenary arch. The builders claim that the arch is earthquake proof and is designed to sway up to 18 inches in either direction in winds up to 150 miles per hour.