Atlantis (DC)

Atlantis was a subaquatic empire, the home of Aquaman.

Sinking
In ancient times, Atlantis was once a city on an artificial island on the surface of the ocean. But when the Ichthultu attacked, King Poseidon harnessed the great power of the city into a single weapon: a trident. With the trident, Poseidon could destroy Ichthultu's minions and return peace to the island. But having used up the power that kept the city afloat, Atlantis sank beneath the waves.

Forgotten by the surface world, the Atlanteans quickly adapted to their environment. They were able to breathe in water outside their shielded city and created water-capable vehicles.

Rise
When the submarine USS Defiant accidentally trespassed in Atlantean territory, a new crisis erupted. Its crew was rescued, but the nuclear warheads, which King Arthur insisted should remain behind, created a dangerous tension between Atlantis and the surface world. His negotiations with the United Nations were short. But after it was revealed the unrest was instigated by Orm, brother to Arthur, matters quickly subdued.

Notable Atlanteans

 * King Arthur/Aquaman
 * Queen Mera
 * Mareena/Aquagirl
 * Lord Orm
 * General Brak

Superman: The Animated Series

 * "A Fish Story" (Mentioned Only)

Justice League

 * "The Enemy Below"
 * "The Terror Beyond"

Justice League Unlimited

 * "To Another Shore" (Mentioned Only)