Before King Ludwig II of Bavaria built his grotto, he sent a servant boy to visit the Blue Grotto of Capri. The boy soaked up the blue color, sketched the stalagmites, and charged reams to the royal account.

The entrance to the grotto at Neuschwanstein Castle barely registers, except for a slight change in the texture of rock. The seamless surface of mountain as it meets the concrete seals the deception; inside stalagmites hang from the ceiling and reflect the blue of gel lights. Tourists are warned not to touch, for safety reasons; the hanging rocks often fall off and break open.