I haven't seen the manga version, but loved the movie adaptation with Abe Hiroshi in it. @strobe999 linked to the Wiki article for the manga. The story follows

I haven't seen the manga version, but loved the movie adaptation with Abe Hiroshi in it. @strobe999 linked to the Wiki article for the manga. The story follows Lucius, an architect in ancient Rome, who timeslips into modern day Japan. He carries ideas from modern Japan's bathing culture back and builds the public baths of Rome. It's a comedy, but a very informative one at that.