Gavr’inis cairn (around 3.500 B.C.), Île de Gavrinis, Breizh 2017.

The burial chamber is reached from the outside by a 14m long corridor. Of the 29 orthostat slabs that form the sides of the passage, 23 are decorated with carved symbols and patterns.

“It is for its art that Gavrinis is famous. No fewer than twenty-three of it’s twenty-nine upright stones have been carved, not in single or isolated motifs but in a profuse series of compositions so that stone flows into stone or is mirrored by another in patterns engraved in low relief. The art is balanced in panels horizontally and vertically in symbols of which the main elements are concentric arcs and axes. These latter implements have splayed cutting edges like the big, prestige axes from the Carnac Mounds.” - A. Burl

The last stone in my photos has 3 horizontal hand sized holes about 10 cm deep similar to kerbstone 52 at Newgrange (which was built supposedly around 300 years later).