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"Your cousin has a base, it's a fortress, I guess, in the Arctic. Now, we don't know much about it, but we do know it's a place that he's been able to commune with his Kryptonian ancestors."
Alex Danvers to Kara Danvers[src]

The Fortress of Solitude was Clark Kent's sanctuary in the Arctic, which holds information about his dead planet Krypton and allows him to communicate with the A.I.'s of his late ancestors.

Kara Danvers began using the Fortress after becoming Supergirl. Following Clark and Lois Lane's temporary move to Argo City, the Fortress of Solitude became Kara's occasional headquarters for Supergirl.


The Fortress of Solitude is a vast sanctuary hidden somewhere in the Arctic. It appears to be built entirely from either crystal or ice.

The Fortress is usually only accessible via a special key, made from condensed Dwarf star material, which can only be lifted by beings with extreme levels of superhuman strength, as it weighs approximately 500 thousand kilograms (approximately 550 short tons).[1] That said, the fortress has also been accessed in other ways, such as by teleport.

Inside, the compound houses a display of items Superman collected over the years from his adventures, as well as statues of his parents. Also present is some form of interactive computer database.[2]

The facility was maintained by Kelex, who recognized Kal-El and Kara Zor-El, as well as certain friends such as James Olsen and J'onn J'onzz as friendly, but maintained defensive programming against strangers such as Hank Henshaw.[3]


Clark Kent invited his cousin, Kara Danvers, to the Fortress of Solitude several times, though Kara always declined as she thought it would remind her too much of Krypton.[2]

It was mentioned by Alex Danvers to Kara that Superman uses the fortress as a base where he can communicate with his Kryptonian ancestors.[4]

Kelex at Fortress.

Kara and James Olsen visited the Fortress to find information regarding Indigo; Kelex provided the information.[2]

Kara later visited the Fortress seeking out Kal-El's whereabouts and then the purpose of Myriad. Kelex was unable to assist Kara, but when she pointed out the fate of the House of El was at stake, the fortress somehow triggered a hologram of Kara's mother, Alura, who revealed the truth about Myriad's programming.[5]

The Fortress was again visited by Superman and J'onn J'onzz to find information about Metallo.[6]

After Project Cadmus captured Supergirl and extracted a sample of her blood, they sent Hank Henshaw here to gather information about "Medusa". At first, Henshaw was considered to be an intruder, until he used Kara's blood to steal files about "Project Medusa".[3] Later, when Kara showed up at the Fortress of Solitude to learn about the Medusa virus, Kelex considered Kara to be the intruder and attacked her, forcing Kara to destroy Kelex.[7]

Mon-El, Kara and Rhea in the Fortress of Solitude.

Kara lured Mxyzptlk here in order to trick him with a false self destruct and made him type the abort code which happened to be his name backwards to force him to go back to his dimension.[8]

Mon-El and Kara decided to talk to Rhea about calling off the bounty on Supergirl's head. She refused and attacked Supergirl with Kryptonite daggers, nearly killing the Girl of Steel. Mon-El interrupted and decided to go with his mom to save Kara's life.[9]

Nia Nal trained her powers in the Fortress.[10]

Known holographic entities

Known visitors


The Flash

Season 2



Behind the scenes

  • The Fortress of Solitude in the comics is Superman's sanctuary located in the Arctic. It first appeared in Superman #17 (July, 1942), created by Jerry Siegel and John Sikela.
  • For being Superman's Fortress of Solitude, there seems to be overwhelmingly enough information of Supergirl's parentage present within the holographic memory files.
    • This could also have to do with the Fortress being a complete Kryptonian archive, plus the fact that Kara is part of Superman's family, being his cousin.