Advertised in the 1895 Montgomery Ward Catalog, the Mosely Folding Bath Company created a tub disguised as a mirrored wardrobe, which folded down and out of its wood casing into the room, revealing a water heater above.  The bathtub was not connected to drainage plumbing, so it had to be scooped out after use.  I’m not into scooping, but I can’t see why this couldn’t have been ingeniously plumbed — especially if there was a way to keep it dry and unmouldy.  I really like the idea of the seldom-used floorspace that a tub occupies being able to do double duty.  It’s obviously quite similar to a Murphy bed.  Via Tywkiwdbi.
photo source small: TinyHouseBlog
photo source large: TinyHouseBlog