A dolmen or portal tomb is a type of single-chamber megalithic tomb, usually consisting of two or more upright megaliths supporting a large flat horizontal capstone or "table". Most date from the Late Neolithic period and were sometimes covered with earth or smaller stones to form a tumulus. Small pad-stones may be wedged between the cap and supporting stones to achieve a level appearance. In many instances, the covering has eroded away, leaving only the stone "skeleton".
Poulnabrone dolmen, the Burren, County Clare, Ireland
Dolmens in Amadalavalasa, Andhra Pradesh, India
Dolmen at Ganghwa Island, South Korea
Trethevy Quoit – one of the best-preserved in Cornwall, UK dated to around 3500–2500 BCE
A megalith is a large stone that has been used to construct a prehistoric structure or monument, either alone or together with other stones. There are over 35,000 in Europe alone, located widely from Sweden to the Mediterranean sea.
Dolmen at Ganghwa Island, South Korea (c. 300 BC)
Megalithic Batu Brak in Batu Brak District, West Lampung Regency, Lampung Province, Indonesia (c. 2100 BC)
Megalithic grave Harhoog in Keitum, Sylt, Germany (c. 3000 BC)
The largest megalith of the ancient world, found in Baalbek, Lebanon, was quarried during the Roman Empire
