The Ridgeway is an 87 miles (139km) long trail. Mmuch of it following the ancient chalk ridge route used by prehistoric man. It passes to the south of Swindon by Avebury.West Kennet Long Barrow is one of the many prehistoric monuments that are part of the Avebury complex of Neolithic sites. It is one of the most impressive and well-preserved burial chambers in Britain, as well as being one of the most visited.