This double-entranced tumulus was constructed between 4700-4500 b.c.e. The tomb is 28 meters in diameter, 3.2 meters in height, and has a circumference of 120 meters. It sits at an elevation in the landscape that measures 112 feet height. Both entrances are oriented toward 150° southeast, possible aligning the site with the winter solstice sunrise. Substantial kerbs line each of the entryways, and the mound appears to be built in terraces. Several of the large capstones in the 11 meter long passageways appear to be pink granite. The passages appear to be about 4 feet high. The tumulus was discovered in 1873 and has been the site of extensive archaeological investigation since then. The double entrance is rare in Brittany, but more common in Denmark.