Saturnyne
Saturnyne was the home of the Saturnynians. It is thought to have had a large body of water, judging by the amphibious nature of its species. The planet had considerable technological progress, having knowledge of weather control, perception filters, Gallifrey and the events of the Last Great Time War.
At some point in the planet's history, it fell to a mysterious crack in space and time that consumed its skies, and the planet was lost to what a member of its species, Rosanna Calvierri, referred to as "silence". A large number of its species had escape the planet through the crack to 16th century Venice, planning to turn the city into the new Saturnyne for its dying race. (DW: The Vampires of Venice)
The Doctor later sealed the cracks, negating their events; Presumably, this would mean that Saturnyne was never lost, and Rosanna and her brood never came to Earth. (DW: The Big Bang)
