This should be pretty obvious to my long-time friends: the Gateway Arch, 630 feet / 192 meters of stainless steel. (I always capitalize it because it is a deity.) The shape is a catenary arch, what you get if you let a chain droop down from its ends. exactly as wide as it is high. Sure I'm biased but I think it is the most beautiful monumental sculpture in the world. It has different moods at every time of day, season and weather. I never tire of it.