Okay, so it's not quite as bad as it sounds. Turns out these are Cicada Killer Wasps. Yes, they're immense, two inches or more long, about as large as my thumb, BUT they're not like the wasps most of you know. For one thing, they're loners. Oh, you might see a lot of them in one place, but they don't make hives. They are hunters, killing cicadas and katydids and stashing them in burrows with their eggs to nurture their young. The males don't have a stinger at all, and the females? You'd pretty much have to actively attack one to get it to sting you, crushing it with your foot or a bare hand.
And this is why I stood around in the midst of dozens of them, snapping pictures wiith total impunity. They like to nest in loose soil, and there's plenty of it in the tiers of the MLK memorial sculpture.
For more, check out this useful article (scroll down to the bottom): [link]