Varos

Varos was a world located in the constellation of Cetus, originally colonised by humanity as a prison planet for the criminal and the insane. As a result, the decedents of the officers controlled the planet through a grim and violent political system.

Astronomical data
Varos had a pink sky with barren wastelands. While it was colonised by humans, it had several presumably native species, including the Gee-Jee flies, (TV: Vengeance on Varos) clinker moles, sand slugs, and rats. (PROSE: Vengeance on Varos) The Museum of the Last Ones had specimens of extinct species from Varos. (PROSE: The Last Dodo) Varos was one of the few planets with sources of Zeiton-7 and, until the discovery of Zeriton deposits on the asteroid Biosculptor in the 23rd century, was thought to be the only source. (TV: Vengeance on Varos)

History
Humans, ruled by the governor, used the planet as a prison colony until the rare mineral Zeiton-7 was discovered there, prior to 2157. (PROSE: Lucifer Rising) The colonists were kept entertained by televised footage of various tortures and executions of the prisoners. The planet was really ruled by Sil, a Mentor who controlled the sales of Zeiton-7.

By the late 23rd century, the mining era of Varos, the voting population was 1,620,783, not counting the Governor and the Officers. The Sixth Doctor and Peri visited in this time when the TARDIS required Zeiton-7. (TV: Vengeance on Varos)