Easter Aquhorthies stone circle, near Inverurie, Abderdeenshire in north-east Scotland, is one of the best-preserved examples of a recumbent stone circle, and one of the few that still have their full complement of stones.
Credit: Kykeon The Caucasian dolmens represent a unique type of prehistoric architecture, built with precisely dressed large stone blocks. The stones were, for example, shaped into angles, to be used as corners or were curved to make a circle.
Carreg Coetan Arthur, near Newport, Pembrokeshire, Wales. Carreg Coetan Arthur dates from around 3000 BC and is the remains of a Neolithic burial chamber (also known as a quoit). Photograph by Richard Law.