The stone circles at Avebury are thought to date from around 2600BC. The monument consists of a massive outer ditch 421 metres in diameter and 1.35km in circumference. The ditch as we see it today is approximately a third of its original depth, which is estimated to have been around 10 metres when first completed. The bank is believed to have originally risen to a height of about 8 metres. It's breached at four points by entranceways which were originally marked by twin pairs of giant stones that formed part of the great circle. One of these pairs remains complete at the South entrance.

The great circle itself ran around the entire inner circumference of the henge and consisted of 98 stones, the largest weighing in at over 40 tonnes. It's diameter of 335 metres makes it the world's largest stone circle. Within its boundaries, it contained two smaller circles.

The Northern circle consisted of 27 stones, of which four survive. It also contained three huge stones that made up a cove arrangement - two of which survive today. In 2003, English Heritage funded work to straighten one of these stones which was believed to be in danger of collapse. During the excavation, they discovered that the stone ran to a greater depth than expected - 2.2 metres. They subsequently estimated it's weight at over 100 tonnes.

The Southern circle also consisted of 27 stones originally contained a huge, slender obelisk, 7 metres in height and a metre in diameter. This was observed by Stukeley in the 17th Century when it could still be seen lying flat. A handful of stones survive from this circle, along with a curious inner alignment of stones known as the "Z Feature".

Along with the avenues of West Kennet and Beckhampton, Avebury originally numbered around 600 stones. Today, only 76 stones remain visible. A further 20 or more are believed buried. Much of the monument's destruction can be attributed to vandalism carried out in the 17th Century. Although this is popularly ascribed to puritanical fervour, the main motivator appears to have been the availability of cheap stone. The stones that were destroyed were broken up and used for building local houses. The real bout of religious fervour took place in the middle ages when stones were pulled down and buried. On that occasion, the zealots did the monument a favour, preserving the stones under the earth for future generations.

Leading out from Avebury were two avenues of standing stones - Beckhampton and West Kennet. Each of these avenues was over 2km in length and each would have consisted of roughly 200 stones. The Beckhampton avenue is all but destroyed and the West Kennet avenue is documented in its own section on this site.

Although impressive in its own right, Avebury is even more staggering when considered in connection with the wider ritual landscape of which it's a part. West and East Kennet long-barrows are the largest surviving examples of their kind in Britain, while Silbury Hill is the largest pre-industrial man-made mound in Europe.

Even in its current form, it's impossible to visit Avebury without being overwhelmed by the sheer scale of the monument. Along with the undeniable atmosphere of the place, this lends a special quality to Avebury that continues to draw people in their droves. I've lost track of the number of times I've visited, but it's generally at least twice a year. Every visit is different and Avebury always seems to have something new to reveal. It's a very rewarding place.

What makes Avebury unusual as a tourist attraction of this magnitude is that it can be visited at any time of year and there'll still be an opportunity to enjoy a little solitude. Despite the huge numbers of visitors, the scale of Avebury means that it's always possible to find a quiet spot to sit in the sun. Avebury is a unique monument on many levels, and a little quiet contemplation is absolutely necessary if you hope to get any real sense of the place.