The Tombeau des Géants (the Giants’ Tomb), also known as the Roche à la Vieille, is located in the commune of Campénéac, near the edge of the Paimpont forest and close to La Touche-Guérin and the Val sans Retour. This small, closed megalithic cist was built from enormous blocks of red schist. Two long slabs form its sides, while a third large block, believed to have originally served as the cover stone, now lies approximately 8 metres away. The inner chamber measures about 3 metres in length and 1.2–1.3 metres in width, while the main side blocks are around 4 metres long. The tomb was surrounded by stones used for packing and stabilisation, possibly together with a small cairn and the large cover slab now lies beside the chamber. Other nearby archaeological monuments include the Hôtié de Viviane and the Jardin aux Moines, which form part of the wider megalithic landscape of Brocéliande.

 

The Tombeau des Géants is an unusual Early Bronze Age megalithic tomb constructed from stones taken from an earlier Neolithic monument. Archaeological research led by Jacques Briard in 1982 suggests that it was built around 2000–1500 BCE, reusing three menhirs from an earlier alignment dating to approximately 3000–2500 BCE. Two of these stones became the side walls of the tomb, while the third served as its cover slab before falling or being moved approximately 8 metres away. A fourth menhir from the earlier group remains fallen nearby. Excavations uncovered stabilising stones around the chamber, as well as pottery fragments, a flint flake and other stone objects. The monument had already been explored before Félix Bellamy described it in 1896, and another investigation appears to have taken place around 1920.

Visitors can reach the Tombeau des Géants from the car park on the La Touche Guerin road. From the car park, signs point towards a schist cross. The route passes through forest and heathland and follows natural paths, which may be uneven in places.