Gemino City

Gemino City was a settlement on the planet Gemino. It was reduced to ruins in the war between Gemino and Gemina. By the time that the First Doctor, John and Gillian visited Gemino City, it was completely abandoned, although some of its automated defence systems were still operational. The Doctor deactivated one of these, then he and his grandchildren followed a dog out of the city to its owner. (TVC: The Secret of Gemino)