During PvE r2, server admins hosted a quest for players to hunt for Atlantis. Clues were written at spawn to find the lost city, an underground and flooded glowstone structure created by schererererer, Trevorman and LadyCailin.
At least 2 people were required to open the treasure room. One person was required to activate the stone plates on the throne which would open the doors to the treasure room to allow entry and exit. The main treasure was within the treasure room and consisted of a small amount of precious materials such as gold, iron and diamond blocks along with a complete set of chainmail armor.
Atlantis was discovered by jcll on 8 April 2011. He quickly discovered that it would require at least 2 people to access the treasure room and gave directions to Kreeon to come help him. They successfully accessed the treasure room and the treasure itself was split between jcll and Kreeon.
There was an alternate smaller unmarked treasure chest on the lower level of Atlantis. It required wading through a large pool of lava to reach the chest. jcll noticed the chest on a later visit to Atlantis and together with Aharito + several stacks of bread managed to survive the swim through the lava. The treasure in this case was a small amount of precious materials but did not contain special items like the chainmail.
The Atlantis stargate was activated and linked to the regular network once the main treasure inside Atlantis was claimed.