Poulnabrone Dolmen, County Clare. This image was photographed for the Legacy project, a fascinating not-for-profit endeavour to capture the mystifying stone remains of prehistoric sites scattered across the British Isles. Please visit www.thelegacyproject.org.uk for more information.

Republic of Ireland, County Clare, Poulnabrone Dolmen. Poulnabrone Portal Dolmen, an ancient stone tomb dating between 2000 – 2500 B.C., situated on limestone pavement in an area know as 'The Burren'.

England, Oxfordshire, Rollright Stones. The Whispering Knights dolmen is a 5000 year old burial chamber, believed to be part of a Neolithic long barrow