I'd passed through St. Louis on a couple of family road-trips when I was a kid, but we never had time to stop. This past spring, I was there for a work conference; fortunately there was time for morning runs along the Mississippi River...running with my iPhone in hand...

The Gateway Arch is such an iconic landmark, but despite the visual familiarity, it is truly awe-inspiring to stand under its audacity: sheer mathematical simplicity on such a large scale--it's taller than the Space Needle. The arc of steel seems to fall out of the sky, a frozen ray of reflective solidity.