In the Wildstorm Universe, the continent of Atlantis existed in ancient times but as in the mythologies of other worlds, Atlantis eventually sank beneath the ocean.

SPOILERS BEYOND THIS POINT

History

Ancient Earth
The continent of Atlantis was ruled by the Kherubim. However, the D'rahn had already colonized the Earth before the Kherubim and Daemonites landed, millennia ago. The Kherubim formed an alliance with the D'rahn, but soon discovered that the D'rahn were even worse than the Daemonites.

The Kherubim S'ylton, father of Marc Slayton and Lord of Atlantis, turned on the D'rahn and the War of Atlantis started. S'ylton and the human mages Tapestry, Azrum and Haroth devised a way to trap the D'rahn's leaders. Despite all their power, the D'rahn were vulnerable to magic and S'ylton trapped them within the great Pyramid of Atlantis, then sacrificed himself, while the mages cast their spell to make them sleep. While the D'rahn's leader Lord Typhon and a small group of his chosen were sleeping, the D'rahn homeworld, known as the Hive, was destroyed and the other D'rahn all allegedly died.

20th Century
The continent of Atlantis was raised from the depths of the ocean when the wizard Haroth obtained Lord S'ylton's ring from Jodi Slayton, Marc Slayton's daughter. The ring, along with the Scroll of Displacement, was what Haroth needed to complete the task. He then proceeded to awaken the D'rahn.

Pildra, Zenthrue, Syth, and their leader Lord Typhon were the only surviving D'rahn. They battled against Backlash and his companions and proved too much for the heroes. Pildra used the D'rahn ability of Enlightenment to evolve Haroth to his next evolutionary state in order for him to help them learn about the new age of Earth. The D'rahn then ordered Haroth to sink Atlantis back into the depths of the ocean (Backlash #30).

Other uses:

New Atlantis
At one time, Lilitu mentioned that starting a war with The Cabal would be unwise because it would slow the construction of New Atlantis (Backlash #13). Since Lilitu and her forces were defeated by Backlash and his friends, it is unclear what she meant by this statement.