The Atlantis Expedition is Earth's international mission to the Ancient city of Atlantis in the Pegasus Galaxy. The impetus for the mission was the discovery of the Ancient outpost in Antarctica, which SG-1 used to destroy the attacking fleet of the Goa'uld Anubis. After discovering the location and fate of the abandoned settlement, the Expedition took up residence and began exploring the worlds of this new, unexplored galaxy, forging alliance with native races and steadfastly opposing the dominance of the Wraith.