Tora

 was a planet in the Crab Nebula that was was home to Ly-Chee for more than 30 of its years. The Seventh Doctor once visited the planet because one of its mountains, Kabuki, was said to be the best place for peace and quiet in that galaxy. Though it was debatable whether the Seventh Doctor actually found the rest he was looking for, he did find a travelling companion. He and Ly-Chee went on to have many adventures together, before the Doctor returned to the planet to drop off a Ly-Chee grateful to be returned to the planet. (IHP: The Enlightenment of Ly-Chee the Wise)