UNIT Trigger Station
Martha travels to the secret UNIT station beneath a castle in Germany in episode 4x13 “Journey's End”.
House of Calvierri (round courtyard)
The Doctor and Rory emerge from the tunnels in the middle of this courtyard and are surrounded by vampire ladies in episode 5x06 “The Vampires of Venice”.
Natty Longshoe's Castle
Clara leads the punishment platoon to a defensible position in the castle in episode 7x12 “Nightmare in Silver”.