Avebury's stones were not only raised by Neolithic builders, they were later broken up by their descendants, and then partly put back by a marmalade heir.
Buried and burned
Medieval and early modern villagers toppled and buried some of Avebury's sarsens, apparently for farmland and out of religious disapproval of a pagan monument standing over their fields. One toppled stone, excavated in 1938, was found lying over the skeleton of a man crushed beneath it, with scissors and coins in his clothing suggesting a fourteenth century barber-surgeon; the stone had evidently been undermined for burial and fell on him. Others were broken up for building material by a method of heating and dousing the sarsens until they cracked.
Keiller's reconstruction
Alexander Keiller, heir to the Keiller's marmalade firm and a trained archaeologist, bought land in and around the monument in the 1930s and funded systematic excavation. Where a stone had been destroyed, Keiller marked its former position with a short concrete pillar, so the circles read today as a mix of original sarsens and modern markers rather than a fully intact prehistoric monument.
A village still inside it
Avebury is unusual among British megalithic sites for having a living village built partly within the earthwork, so restoration had to work around houses, roads and a churchyard rather than an empty field.