Mechanoid City

The Mechanoid City was a city built and inhabited by Mechanoids on the planet Mechanus. When Steven Taylor crashed on the planet, the Mechanoids captured him and held him prisoner in the city. Two years later, the Doctor and his companions arrived on Mechanus and were also taken to the city, where they met Steven. The pursuing Daleks entered the city and attacked the Mechanoids. The Doctor and his friends escaped the Mechanoid City just before it, the Daleks and the Mechanoids were all destroyed. (DW: The Chase)

A Mechanoid City also appears in Impasse, although it is unclear if this is the same city.