The Avebury henge is the largest stone circle in Europe and one of the most significant Neolithic monuments in the world, designated a UNESCO World Heritage Site alongside Stonehenge. The outer circle consists of up to 100 sarsen stones — large sandstone boulders quarried from the Marlborough Downs — arranged within a massive earthwork ditch and bank that was itself an enormous undertaking, dug using antler picks around 2850 BC.
Two smaller stone circles sit inside the outer ring, though many of their stones are missing. Medieval villagers, frightened of the monument's pagan associations, toppled many stones and buried others; some were later broken apart for building material. The 18th-century antiquary William Stukeley documented the circle while stones were still being destroyed, and his records help archaeologists reconstruct what the full monument looked like. Today the site is managed by the National Trust, who have re-erected several fallen stones in their original positions. Entry is free; the car park charges a small fee.