Dolmens are tombs dating from about 2000 BC and consist of two or more unhewn stones supporting a flat capstone. There is a huge one at Kilternan ,Co. Dublin. Others are at Proleek, (Picture) Co Louth, Knockeen (Picture) Co. Waterford, Kilclooney Co Donegal, Poulnabrone Co Clare, Dolmen of the Four Maols Co. Mayo and Legananny,Co . Down.