Kryptonopolis, formerly known as Krypton Island, is an island recreation of the planet Krypton, and named after the planet's capital city, Kryptonopolis. It was founded by Jonas T Smith. The island allows people to buy property there, living in an idealized, futuristic setting. The island also claims to be free of crime, as all incoming citizens must undergo a background check with the FBI. ("Krypton on Earth")
The island was originally created as part of Jonas Smith's get-rich-quick scheme, but once Superman caught on to the criminal's illegal activities, the island was allowed to continue under new management. ("Krypton on Earth")