The World
From Tardis Wiki, the free Doctor Who reference
The World was a human colony ship sent out some time after Zoe Heriot's time, during a time of great strife on the planet Earth. Unbeknownst to the people boarding and building it, the psychic entity known as Corvus was aboard at this time.
The World was active for around 600,000 years before the effects of the Corvus caused it to go into disrepair, allowing it to drift deep space.
900,000 years later, the Second Doctor, Jamie, and Zoe arrived on the World concurrently with a human expedition, and helped to defeat the Corvus. (AUDIO: The Wreck of the World)
