Er-Grah Tumulus

(3300 BC) The Er-Grah Tumulus is a Neolithic passage grave in Locmariaquer, Brittany, part of the Locmariaquer Megalithic Complex[1][2]. Measuring 140 metres (459 ft) in length, it was originally constructed in the fifth millennium BC as a cairn before being extended in both directions[1]. A paved pavement surrounded the stepped structure, and the placement of its capstone indicates completion around 3300 BC[1]. This monument forms part of a complex that also includes the Table des Marchand dolmen and the Broken Menhir of Er Grah—the largest single stone block ever erected by Neolithic peoples[2].