Ancient Ark of the Atlanteans

From the introduction: When the inhabitants of the continent Atlantis saw the end coming they created a giant ark out of the smaller of Earth's two moons. They went away and never looked back, trying to find a new place to live, never noticing that the removal of the second moon averted the disaster. 15.000 years later their ark is still slowly making it's way through space, the inhabitants having long forgotten the purpose of their world and their own history. They are content to live, strife and die in their own small universe, creating civilizations and destroying themselves in an endless circle.