Rocher des Faux Amants
'The Rock of the False Lovers'
Morgan Le Fay is said to have turned her lover Guyomard and the lover he betrayed her with, into rocks, which today is known as Rocher des Faux Amants. Its located on the ridges of the Val sans Retour ('Valley of No Return'), and overlooks the Fairy Mirror.
This crag in Brittany contains a cave known as Merlin's House, where the sorcerer was supposed to have sojourned. The cave could be turned around so it never faced the wind, or even moved underground if the wind blew from every side.