The Fortress of Solitude is a fictional fortress appearing in American comic books published by DC Comics, commonly in association with Superman. A place of solace and occasional headquarters for Superman, the fortress is typically depicted as being in frozen tundra, away from civilization. Its predecessor, Superman's "Secret Citadel", first appeared in Superman #17, where it was said to be built into a mountain on the outskirts of Metropolis. By issue #58 it is referred to as the Fortress of Solitude, seems at a glance to be a freestanding castle, and is said to be located in a "polar waste". When the Fortress reappears in 1958 and for the first time takes center stage in a story, it is again an underground complex in a mountainous cliffside.
