Avebury is a Neolithic henge monument containing three stone circles, around the village of Avebury in Wiltshire. It is owned and managed by the National Trust.
Wandering through the web looking for information on Avebury and the area around I found this excellent personal site http://www.avebury-web.co.uk/index.html which has lots of information and some fine photographs. It's well written and is worth taking a few minutes to browse through it if you have any interest in times past.