Mencken in discussing UK education mentions as a bit of trivia that every UK school kid is presumed to know,"Balbus built a wall". I have yet to find a word about Balbus' wall. I did find a fairly detailed biography of him at:
http://www.geocities.com/Athens/Olympus/6311/bal_bio.html
Interesting to me, the bio said it is believed that his name came from a root meaning "stammerer", probably applied to one of his ancestors. That interested me, as "balbutier"
is French verb meaning to stammer.
I have yet to find a single word about his wall, though.