Practical guide with 53 large scale maps (1:20,000). The Ridgeway begins near Avebury and runs 87 miles across the high chalk downs of Wiltshire, into the Thames Valley and on to the Chiltern Hills of Buckinghamshire, finishing at Ivinghoe Beacon near Aylesbury. This is the oldest road in Britain, some of it dating from prehistoric times. It's a ......