What’s That? #4

Welcome back to What’s That?, the weekly game on GGW.

It’s week #4 and I haven’t been able to stump the faithful readers of this site.

Each week, I show small close-up photographs of three different well-known places in and around Washington, DC. The first person to get all three wins recognition of his or her genius when I reveal the answers a few days later.

Here’s the set for this week:

Post your guesses in the comments. Comments won’t appear by default to avoid spoilers, but you can click to see them (ideally after you take a guess yourself).