Gehanna

From Tardis Wiki, the free Doctor Who reference

Gehanna was a planet which had twelve human cities. Each of the cities was separate and numbered, from City One through to City Twelve, and consistently purchased and scavenged alien technology in order to update their own societies. When the Twelfth Doctor arrived on Gehanna, each of the cities except for City Twelve had fallen to a "plague" of Weeping Angels. (PROSE: Grey Matter)