Italy: Pompeii

An ancient "steam room", used by the residents of Pompeii before Vesuvius's infamous eruption. Warm water, heated by the flames fanned below the floors, evaporated up from the large basin in the center. This provided a comforting, radiant, moist heat. The humidity would rise and condensation would collect on the ceiling and then run down the purposely-placed, functionally-decorative lines in the arched ceiling, ensuring the cycle would continue without patrons having to bother with water dripping on their heads. So smart!