Monumental engineering
The Avebury Henge is an example of Neolithic construction, built and modified between 2850 and 2200 BCE. The monument's main feature is a massive circular earthwork, a bank and an internal ditch, that covers 11.5 hectares (28.5 acres). This ditch was originally cut up to 10 meters deep into the chalk bedrock, with the excavated material used to create an outer bank that stood about 5 meters high. From the bottom of the ditch to the top of the bank, the total height was once 16 meters. The entire earthwork has a circumference of nearly a mile.
Inside this enclosure stands the largest prehistoric stone circle in the world, originally composed of around 100 sarsen stones. This Outer Circle, in turn, contains two smaller, separate stone circles. The northern inner circle once had 27 stones, including a three-sided formation called "The Cove." The southern inner circle was made of 29 stones and featured a central, 6.4-meter-high monolith called the "Obelisk," which is no longer present. The stones themselves are an unworked, local type of silicified sandstone called sarsen, sourced from the Marlborough Downs just a few kilometers away. The largest of these stones weighs over 100 tonnes. Two ceremonial avenues of paired stones, the West Kennet Avenue and the Beckhampton Avenue, once led away from the henge, connecting it to other sites in the landscape.
Destruction and rediscovery
After its use in the Neolithic and Bronze Age, the site was largely abandoned. During the medieval period, many of the standing stones were deliberately toppled and buried. This destruction, which began around 700 years ago, is sometimes attributed to early Christian zeal against pagan monuments. Later, in the 17th and 18th centuries, more stones were broken up for use as local building materials. The process involved heating the stones with fire and then dousing them with cold water to fracture the rock.
The site’s appearance today owes a great deal to Alexander Keiller, the heir to a marmalade fortune, who purchased the site in the 1930s. Appalled by the monument's state of neglect, Keiller funded a massive archaeological project between 1934 and 1939. He and his team excavated large areas, located the buried stones, and re-erected them in their original stone-holes. Where stones were missing entirely, Keiller placed concrete pylons to mark their former positions. His work cleared away overlying buildings and restored much of the monument, preserving it for the future. In 1943, Keiller sold the land to the National Trust. Today, Avebury is part of a UNESCO World Heritage Site, recognized for the Neolithic and Bronze Age landscape.