Castle Dracula

 was a stronghold of Dracula which he called "the proudest achievement of my reign". It was a tactically important location, which was almost impossible to impregnate. Since it was on a high hill overlooking a flat plain, any approaching armies would first have to make themselves vulnerable to archers in the castle ramparts.

After his engagement to Erimem, he took the former pharaoh to the castle, which caused Peri and the Fifth Doctor to follow. (AUDIO: Son of the Dragon)