Probably, Avebury Stone Circle is as well known as Stonehenge, both being among Britain's most important prehistoric sites. Dating from around 2500BC, Avebury Stone Circle covers some 28 acres, and comprises three main features: the perimeter ditch and bank; the outer circle of stones; and two small, inner stone circles.

Ninety miles west of London and twenty miles north of Stonehenge stands Avebury, the largest known stone ring in the world. Older than the more famous Stonehenge, and for many visitors far more spectacular, the multiple rings of Avebury are cloaked with mysteries which archaeologists have only begun to unravel.

A circular ditch and bank approximately a quarter of a mile (0.4km) in diameter, encompass the site, the ditch still very visible even though it is now only one-third of its original depth of 30ft (10m). Running around the inner perimeter of the ditch and bank, is a circular group of Sarsen stones - similar to those seen at Stonehenge - the western half of the ring surviving to a greater degree than the eastern half.

Similar to Stonehenge and many other megalithic monuments in the British Isles, Avebury is a composite construction that was added to and altered during several periods. As the site currently exists, the great circle consists of a grass-covered, chalk-stone bank that is 1,396 feet in diameter (427 meters) and 20 feet high (6 meters) with a deep inner ditch having four entrances at the cardinal compass points. Just inside the ditch, which was clearly not used for defensive purposes, lies a grand circle of massive and irregular sarsen stones enclosing approximately 28 acres of land. This circle, originally composed of at least 98 stones but now having only 27, itself encloses two smaller stone circles. The two inner circles were probably constructed first, around 2600 BC, while the large outer ring and earthwork dates from 2500 BC. The northern circle is 320 feet in diameter and originally had twenty-seven stones of which only four remain standing today; the southern circle is 340 feet across and once contained twenty-nine stones, of which only five remain standing.

Contained within the outer ring were two smaller stone circles, one each to the North and South of the site, which are now separated by the modern village High Street. The southern ring has survived to a greater degree than its northern counterpart, and once contained a large standing stone named the 'Obelisk' which has, sadly, been destroyed. A concrete marker is the only reminder of its original position. There also appears to have been a rectangular arrangement of stones, six of which still survive.

The northern inner circle has largely been destroyed, with the exception of two large stones - originally part of a group of three in a cove-shaped arrangement - known as the 'cove'. Unfortunately much damage was caused to the circles during the 18th century when local people were clearing the land to improve their farming, but many of the missing stones have been identified from drawings. These drawings, made by William Stukeley, were the result of several surveys he undertook at Avebury Stone Circle, and his findings were published in 1743.

Today, Avebury Stone Circle has four entrances but possibly had only two - one North and one South - before the modern roads cut through the site. From the main entry points, ran two great avenues flanked on either side by a row of smaller stones. West Kennet Avenue on the southern side still exists for a short distance, but Beckhampton Avenue to the north, is all but lost.