Avebury is a Neolithic henge monument containing three stone circles, around the village of Avebury in Wiltshire, in southwest England. Unique amongst megalithic monuments, Avebury contains the largest stone circle in Europe, and is one of the best known prehistoric sites in Britain. It is both a tourist attraction and a place of religious importance to contemporary Pagans.

Constructed around 2600 BCE, during the Neolithic, or 'New Stone Age', the monument comprises a large henge that is, a bank and a ditch. Inside this henge is a large outer stone circle, with two separate smaller stone circles situated inside the centre of the monument. Its original purpose is unknown, although archaeologists believe that it was most likely used for some form of ritual or ceremony. The Avebury monument was a part of a larger prehistoric landscape containing several older monuments nearby, including West Kennet Long Barrow and Silbury Hill.

By the Iron Age, the site had been effectively abandoned, with some evidence of human activity on the site during the Roman occupation. During the Early Mediaeval, a village first began to be built around the monument, which eventually extended into it. In the Late Mediaeval and Early Modern periods, locals destroyed many of the standing stones around the henge, both for religious and practical reasons. The antiquarians John Aubrey and William Stukeley however took an interest in Avebury during the 17th century, and recorded much of the site before its destruction. Archaeological investigation followed in the 20th century, led primarily by Alexander Keiller, who oversaw a project of reconstructing much of the monument.