Atlantis is a LEGO System playtheme released in January 2010. It revolved around a team of underwater explorers searching for the sunken city of Atantis and its sets involved models of futuristic submarines, giant sea monsters as well as ancient ruin sites. The theme also features several new minifigure head molds as well as a new breathing apparatus among other new elements, specifically the exclusive keys, which are currently available in five different variations, with pictures of water creatures ranging from Crabs and Squids to Sharks, Manta Rays, and Turtles.
Atlantis features a group of explorers that are searching the sea floor for the eponymous lost city from ancient myths. They are equipped with a wide array of futuristic underwater vehicles colored in red with neon-green windows. During their quest they encounter giant guardians as well as the warriors of Atlantis, a strange kind of sea creature that resemble the body of a minifig with the heads of manta rays, sharks and squids. The sets of this theme feature either the vehicles of the explorers, ruin sites or single guardians.