The site is formed by a huge circular bank rising up some 30 foot and stretching round for a mile, a large ditch that is only half its original depth and a ring of 98 sarsen slabs. Within this outer circle and earthworks are two smaller circles formed with 30 stones in each.
The stones, each weighing about 40 tons or more, were left rough and not 'dressed' as were the Stonehenge blocks. They were brought from the same place, the nearby Marlborough Downs. Now there are only 27 in place, because a few hundred years ago many of the stones were broken up and used to construct the present village which grew up within the earthworks.
In the 14th century some of the stones were buried. In that period, as pits were been prepared to bury the stone, a man was killed by one of the stones falling over unexpectedly into the pit which was being prepared for its burial.
Other remarkable stones are the Swindon Stone, the largest (it weighs about 60 tons), the Devil's Chair (local legends attribute mystic powers to the stone such as the ability to summon the devil if you run round it 100 times anti-clockwise) and the Repaired Stone, which has been reconstructed in an odd shape.
More photos from here at Flickr....http://www.flickr.com/photos/ian_forsyth/sets/72157623755944465/