Carisbrooke Castle, England
Cliffside Castle, Renne, France photo via redsungiant
Castillo de Butròn in Gatika, Basque Country, Spain
Olaf's Castle, is located on a small rocky islet in Lake Saimaa in Savonlinna, Finland.
Waterfall castle in Poland
Mysterious Peterhof, Russia. Looks like a beautiful version of the castle in the sea, from Ink Heart.
Neuschwanstein Castle, Bavaria, Germany photo via besttravelphotos