megalith

A large stone used to construct a structure or monument, such as a tomb or a stone circle. The term megalithic describes structures made of such large stones, especially during the Neolithic period in Europe. See also: menhir, dolmen, henge, cromlech, trilithon.

Carnac_megalith_alignment_2

Alignment of megaliths. Neolithic. Ca. 4500–3300 BCE. Carnac, France.