Makorna

Makorna was an uninhabited planet.

There was a flourishing civilisation there, but it died out, leaving nothing but ruins. Ohica banished Iris Wildthyme to the planet for her interference in the Sisterhood of Karn's affairs. After finding out from one of the archaeologists exploring Makorna about the Third Doctor's exile on Earth, Iris got drunk, summoned Verdigris, and sent him to free the Doctor.

When Verdigris' machinations with the Meercocks were revealed, Iris promised the Doctor that she would help them settle on Makorna, but he doubted whether she had. (PROSE: Verdigris)