Taken in November of 1918, these two photos show the inside of the UB-110 German submarine. The valves were used to control the submarine and the reverse image is of four torpedo tubes used against a merchant ship in July 1918. Soon after the attack the submarine sunk and later was salvaged, but scrapped.

Follow the link to see much larger images: [Tyne and Wear Archives via Twisted Sifter]

The Control Room of a German Submarine from 1918