Mechanistria

Mechanistria was a planet and the home to the Korad.

Astronomical Data
Mechanistria was an Earth-like planet, orbiting a yellow sun and having a similar atmosphere. Originally, Mechanisria had forests, mountains and oceans like any other planet, but the Mechanistrians later tore them all down and covered the whole planet in metal. After the meddling of the First Doctor, this future was undone and the planet was kept in its verdant state. (DWA: Peril in Mechanistria)

History
Mechanistria, once known as Korad, was a green world similar to Earth and was home to a near-human race, known as the Korad. At some point in the Korads' technological evolution, the race split in two with the mechanic\lower class continuing to be known as Korad and the ruling upper class known as Mechanistrians or Wise Ones. The Mechanistrians began melding their brains to the machines, which took control of the planet. The forests, mountains and oceans were destroyed to make way for more machines Soon, the machines were the effective rulers of the planet, keeping the Korads only for repairs. Though some revolts were attempted, they were crushed, leaving the Korads in their servitude. This continued for nearly 10 million years.

When the First Doctor came to the planet after an incident with the Daleks, he was taken by the Korads to one of their underground havens. When he told them of his TARDIS, the Korad Drako planned to use it to go back in time and remove the mechanical influences from the planet. Though Beran and the machines tried to stop him, the Doctor and Drako were able to get to the TARDIS. With it, Drako was brought back in time and was able to negate the future. (DWA: Peril in Mechanistria)