Caption:
A dolmen with a circuit of stone (cromlech) in the parish of Constantine, Cornwall. A dolmen is a type of single-chamber megalithic tomb, usually consisting of two or more vertical megaliths supporting a large flat horizontal capstone. Most date from the early Neolithic (4000–3000 BC) and were sometimes covered with earth or smaller stones to form a tumulus. It remains unclear when, why and by whom the earliest dolmens were made. A cromlech, cromleh or cromlêh is a megalithic altar-tomb, made of rough stone. Image taken from Primitive Man by Louis Figuier, 1870 (cropped and cleaned)..