The first time I drove past that arch I didn’t stop. I didn’t get too close – still, it was big. Much taller than all the buildings around it. Twenty-four years later I went back and took a closer look.

The arch is part of the Jefferson National Expansion Memorial in Saint Louis. It was designed by Eero Saarinen in response to a design competition in 1947, and built between 1963 and 1965. It stands 630 feet, or 192 meters, high.

There’s a film you can watch, in the museum under the arch, which shows how they built it. It’ll hold you spellbound. Especially the part where the guys building it wandered around up there, nonchalantly smoking cigarettes, not a harness in sight.

It’s a flag for Manifest Destiny, planted at the launching point of the Lewis and Clark Expedition. It’s the tallest arch anywhere on earth. According to the park site, the lift to the top is closed for renovation, until March 2017 at the earliest. Still, go and see it. Just reserve your “tram” time in advance. (Bring wide cameras. That thing won’t fit in your viewfinder.)