Original version
The concept and name "Fortress of Solitude" first appeared in the Doc Savage pulps in the 1930s and 1940s. Savage built his Fortress of Solitude in the Arctic and retreated to it alone to make new scientific or medical breakthroughs, and to store dangerous technology and other secrets. The Golden Age Superman did not have an arctic fortress, but instead a "mountain sanctuary" which was located in a mountain range on the outskirts of Metropolis. Here, Superman kept a diary, oversized tools for various projects, and other equipment and trophies.
Superman's Silver Age Fortress, which debuted in 1958, was also located in the Arctic and served similar purposes. Built into the side of a steep cliff, the Fortress was accessible through a large gold-colored door with a giant keyhole, which required an enormous key to open it. The arrow-shaped key was so large that only Superman (or another Kryptonian such as Supergirl) could lift it; when not in use, the key sat on a perch outside of the Fortress, where it appeared to be an aircraft path marker. This was until a helicopter pilot followed the direction of the arrow straight to the entrance of the Fortress, forcing Superman to develop a cloak to camouflage the entrance and key and to ensure the Fortress's secrecy.[4] According to Action Comics #261, Superman first established secret Fortresses in outer space and at the center of the Earth before settling on an Arctic location.[5]
The Fortress contained an alien zoo, a giant steel diary in which Superman wrote his memoirs (using either his invulnerable finger, twin hand touch pads that record thoughts instantly, or heat vision to engrave entries into its pages), a chess-playing robot, specialized exercise equipment, a laboratory where Superman worked on various projects such as developing defenses to kryptonite, a room-sized computer, communications equipment, and rooms dedicated to all of his friends, including one for Clark Kent to fool visitors. As the stories continued, it was revealed that the Fortress was where Superman's robot duplicates were stored. It also contained the Phantom Zone projector, various pieces of alien technology he had acquired on visits to other worlds, and, much like the Batcave, trophies of his past adventures.[1] Indeed, the Batcave and Batman himself made an appearance in the first Fortress story. The Fortress also became the home of the bottle city of Kandor (until it was enlarged), and an apartment in the Fortress was set aside for Supergirl.
A detailed depiction of the Fortress and its contents forms the background to DC Special Series #26 (1981); "Superman and his Incredible Fortress of Solitude", in which Superman minutely inspects the Fortress, suspecting an enemy has planted an Earth-destroying bomb within it. Another noteworthy appearance of this version of the Fortress was in 1985's Superman Annual #11, a story by Alan Moore and Dave Gibbons titled "For the Man Who Has Everything", in which it served as a battleground for Superman, Batman, Robin, and Wonder Woman against the alien would-be overlord Mongul. This story was adapted to animation in the 2004 TV series Justice League Unlimited.
Additionally, Superman established an undersea Fortress of Solitude – hollowed out of the side of an undersea cliff – in September 1958. The undersea Fortress, which is reportedly located at the bottom of the Sargasso Sea at 28 degrees North latitude, 50 degrees West longitude, is stocked with numerous exotic ocean relics and is equipped with sophisticated monitoring apparatus to enable Superman to keep abreast of events occurring throughout the seven seas. Superman later abandoned the undersea Fortress and the structure is now used by the mer-people of Atlantis as a showplace and a tourist attraction.
The original version of the Fortress of Solitude made its last appearance in the 1986 non-canonical (or "imaginary") story "Whatever Happened to the Man of Tomorrow?". In this story, under constant attacks by returning foes, Superman goes to ground inside the Fortress, taking his closest friends with him for their protection. The villainous android Brainiac soon besieges the Fortress with various allies, surrounding it and the outlying territory with an impenetrable force field to keep Superman's fellow heroes from aiding him. Superman battles Mister Mxyzptlk, who was behind the plot to destroy him. As Superman was forced to destroy Mxyzptlk, breaking his vow against killing, he exposes himself to gold kryptonite to permanently remove his powers and then appears to leave the Fortress to freeze to death in the Arctic cold. Superman is never seen again, although we find out in a "ten years later" wraparound segment set in 1997 that he survives as Jordan Elliot, husband of Lois Lane Elliot, and that they are the parents of toddler Jonathan Elliot, who has super-powers.[6][7]
