Sanctuary (The Golden Door)

The Sanctuary, located on Bukol, was a gateway to another dimension. It was set up by the Time Lords in their distant past. The Doctor first learned about it during his time in the Matrix.

The Sixth Doctor brought two Maleans, Orsa and Alëza to the Sanctuary, so they could escape Mykloz, who was sent to kill them. (PROSE: The Golden Door)