Rocamadour, France is built on a rock in the middle of the Causse de Gramat. This is a vast slate plateau and part of the Causse du Quercy. The city is the most visited pilgrimage site after Lourdes in France.
Although this is not a castle it is one of it best places I've ever visited in Germany. I had no other place to put it. Rothenburg ob der Tauber, Germany - 101 Most Beautiful Places You Must Visit Before You Die! – part 2