Merlin's Cave, Tintagel , United Kingdomcaves, seashores,

Merlin's Cave is the name given to a cave located beneath Tintagel Castle, 5 kilometres (3.1 mi) south-west of Boscastle, Cornwall. It is 100 metres (330 ft) long, passing completely through Tintagel Island from Tinagel Haven on the east to West Cove on the west. It is a sea cave formed by marine erosion along a thrust plane between slate and volcanic rocks.

Tennyson made Merlin's Cave famous in his Idylls of the King, describing waves bringing the infant Arthur to the shore and Merlin carrying him to safety.