The last party-goers seem to have cleared up very carefully after the final celebration at Marden Henge (Wilthsire, England), approximately 4,500 years ago. All left-overs from the feast - the pig bones, the ashes and the burnt stones from the barbecue that cooked them, the broken pots and bowls - were tidied up into a dump to one side. A few precious offerings were carefully laid on the clean chalk, one of which included an exquisitely worked flint arrowhead. Then the revellers covered the whole surface with a thin layer of clay, stamped it flat, and departed. Forever.

In the past two weeks, English Heritage archaeologists have removed the thin layer of turf covering the site, which has miraculously escaped being ploughed for more than 4,000 years. They were astonished to discover the undisturbed original surface just as the prehistoric Britons left it years ago. "We're gobsmacked really," said site director Jim Leary.