They were covered by a stone cairn or earth barrow.
Examples with outer areas, not used for burial, are also known.
The word 'megalith' comes from the Ancient Greek It has been used to describe buildings built by people from many parts of the world living in many different periods.
A variety of large stones are seen as megaliths, with the most widely known megaliths not being sepulchral.
Prominent examples include the sites of Brú na Bóinne and Carrowmore in Ireland, Maes Howe in Orkney, and Gavrinis in France.
The third tomb type is a diverse group known as gallery graves.
Examples of stone circles are also found in the rest of Europe.It normally consists of a square, circular or cruciform chamber with a slabbed or corbelled roof, accessed by a long, straight passageway, with the whole structure covered by a circular mound of earth.Sometimes it is also surrounded by an external stone kerb.Many of these, though by no means all, contain human remains, but it is debatable whether use as burial sites was their primary function.Though generally known as dolmens, many local names exist, such as in Wales.