The Cairn of Barnenez (4850 BC) is a Neolithic monument located in Brittany, France. It is considered one of the earliest megalithic monuments in Europe. It is also remarkable for the presence of megalithic art. The Barnenez cairn is 72 m long, 25 m wide and over 8 m high. It is built of 13,000 to 14,000 tons of stone. It contains 11 chambers entered by separate passages.