The Paimpont Forest has been identified with the Broceliande of the Arthurian legends since medieval times.
The identification of this megalithic tomb as Merlin's, however, dates to someone's flight of fancy in the 19th century.
Merlin's or not, I like the place and wanted to post the pictures. If you think it's off topic, too bad. It's my blog.
The "House of Viviane."
The "Giant's Tomb."
The "House of Viviane
The Fountain of Barenton.
The "monks' garden."