The Crystal Caves, also known as the Casterwill Caves, are a Casterwill base located in northern coast of England. The magic of Lord Casterwill courses through the large, blue crystals within the caves. The caves are the home of Nimue Casterwill, the Lady of the Lake, as well as Viviane Casterwill, her granddaughter. The two means of entering the caves are through an entrance on the other side of the cliffs and through a portal near the beach which could be opened by the Lady of the Lake.