Lisa, the first floor women's restroom at the Museum of American
History still has the bathroom history exhibit (if you call a couple of
paragraphs, several illustrations, and a length of pipe an exhibit).
Don't ask me how I know. Unfortunately, the corresponding display in the
men's room was removed some time ago. I believe the bathroom displays
were a brainstorm of Daniel Boorstin when he was director, which would
date them to the late 1970s. I never thought this idea was carried far
enough, but I imagine there might have been a fear that a more extensive
exhibition would have interfered with traffic flow (pardon the
expression). But I was never PRIVY to this project, so I can only guess.
--David Haberstich