The Val sans retour, also known as the Val des faux amants or the Val périlleux, is a mythical site from Arthurian legend, as well as a physical site located in central Brittany, in the Paimpont forest. The legend attached to it is primarily recounted in the Lancelot-Grail: in it, Morgan le Fay experiences a disappointment in love with the knight Guiomar, and, in retaliation, creates the Val sans retour in the forest of Brocéliande, where any knights unfaithful in love are imprisoned.
The physical site in the Paimpont Forest became a popular tourist site due to its links to Arthurian legends. It has different points of interest including the Golden Tree and the Fairy Mirror in its valley, as well as Viviane’s house and Merlin’s seat on its ridges. It is home to numerous species of flora and fauna and protected as a natural zone of ecological interest, fauna and flora, as well as a Natura 2000 site.