Dolmen

A dolmen, also known as a cromlech 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. They were originally commonly covered with earth to form a barrow.^[1][2]

Most dolmens date from the Late Neolithic period (4000–3000 BCE).^[3] At various times in the past they have been supposed to be druid’s altars, but that supposition is inconsistent with the dating evidence.^[2]