Water tower

A water tower stored water. West Barnton Airfield had one but it was destroyed by the sentient iron. (COMIC: The Metal Eaters)

During the 1938 radio broadcast of The War of the Worlds, some Americans thought that Martians had really invaded Earth (AUDIO: Invaders from Mars) and saw water towers as Martian tripods. (PROSE: Elementary, My Dear Sheila)