Mount Perdition

Mount Perdition was a mountain on the planet Gallifrey. Its slopes were covered with vast fields of red grass. The Master's father owned land on Mount Perdition's slopes. (TV: The End of Time)

During the Last Great Time War, the Celestial Intervention Agency had a base on Perdition. (AUDIO: Darkness and Light)

Behind the scenes
Perdition is described in Christian theology as a state of external punishment and damnation into which a sinful and unpenitent person passes after death.