Seeing a Building's History Clearly

What Do You Think You're Looking At? #69

A few times I’ve passed these buildings in Maryland—the first on Maryland 355 in Gaithersburg, and the second on Annapolis Road in Lanham—and I’ve always wondered what they used to be. I know I’ve seen the building type before, but I couldn’t remember what it was.

There’s no hint here; either you know it or you don’t, and I didn’t.