The planet where Atlantis, the lost city of the Ancients, slumbered underwater for many thousands of years following the Ancients' devestating war with the Wraith. The war led to a Wraith assault on the planet -- which was the center of Ancient activity in the Pegasus Galaxy.
Not long after the arrival of the Atlantis expedition from Earth, the city's power reached critical lows and an automated mechanism rose the city to the surface to prevent its destruction -- though it left the city vulnerable to attack from above.
A large portion of the planet's surface is water, and the raised city now sits as an island amidst a great ocean. Near the city -- only 25 minutes away by Puddle Jumper -- is a large continent. After it was discovered, the Athosian refugees in Atlantis decided to resettle there, in order to start a new life in relative safety from the Wraith. They are still able to communicate with the city, where the planet's Stargate is located.
Lieutenant Aiden Ford has suggested the name "Atlantica" for the planet.
HOME TO -
Ancients, Atlantis expedition
FIRST APPEARED -
Rising, Part 1
KEY EPISODE(S) -
Rising, Part 1 - The Earth team travels to Atlantis and discovers that the city is on a planet with no signs of land.
Rising, Part 2 - When the city runs out of power, the city automatically rises to the surface of the planet -- where it sits unprotected.
Suspicion - Sheppard and Ford explore the planet with a Puddle Jumper, and discover a land mass near Atlantis -- to which the Athosians resettle.
Grace Under Pressure - The planet's great ocean is explored when a Puddle Jumper accidentally crashes and sinks deep into the sea.