Under the Arch

Stop right here, dead center under the legs, and tip your head straight back until the sky starts to tilt. That bright seam six hundred and thirty feet up — that's where it closed. Two separate legs climbed toward each other for two and a half years, and at the very top they finally became one arch. Now look at the shape of it. It isn't a half-circle. It's a weighted catenary — the exact curve a loose chain makes hanging from both ends, only flipped upside down and made heavier toward the base so it doesn't look like it's about to tip over. A Finnish-American architect named Eero Saarinen drew that curve for a design competition back in nineteen forty-seven, and out of a hundred and seventy-two entries, his won. Here's the number most people walk right past: it stands six hundred and thirty feet tall and it spans six hundred and thirty feet wide — exactly as wide as it is high. The tallest arch in the world, and the tallest man-made monument in America. Seventy-five feet over the Washington Monument, better than twice the height of the Statue of Liberty. And that skin catching the light? Quarter-inch stainless steel, almost nine hundred tons of it, and it never looks the same twice — silver-white at noon, gold at sunset, near black against a storm coming in off the river. Stay under here a minute. There's a whole lot more to how this thing got built than just how tall it is.