Fortress of Solitude

The Fortress of Solitude is a fictional fortress appearing in American comic books published by DC Comics, commonly in association with Superman. It is the place where Superman first learned about his true identity, heritage, and purpose on Earth. The fortress functions as a place of solace/occasional headquarters for Superman and 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.