Carmilla's Castle is a location in the Castlevania animated series. As its name implies, it is a large castle owned by the ambitious and calculative vampire queen, Carmilla. It is an enormous building located in Styria, Austria, which rivals in size and sumptuousness to Dracula's Castle itself. It functions as the headquarters and base of operations for the Council of Sisters, a committee conformed by four powerful female vampires that rule over the land.
The castle has beautiful architecture, with flying buttresses and high towers. Even the dungeon of the castle has a heating system, where hot air is circulated through a series of pipes (likely a hypocaust).
Lenore noted to Hector, who was puzzled by such technology and heating in the dungeon to begin with, that they weren't monsters and that it was a scientific knowledge that vampires preserved, but which was forgotten by humans.