The Avebury square monument

Archaeologists in a stone circle

In 2017 a team of archaeologists let by the University of Leicester and the University of Southampton found a striking and apparently unique square monument beneath the Avebury stone circle. The team used geophysical techniques to look beneath the ground without digging

The main stone circle at Avebury is the largest stone circle in the world, measuring 330m across and originally comprised of around 100 huge standing stones.  Within this outer circle are two smaller circles.

Working in partnership with the National Trust’s own archaeologists, a research team led by the University of Leicester and University of Southampton used a combination of soil-resistance survey and ground-penetrating radar to investigate the stone circle.

Their work was funded by the Arts and Humanities Research Council (AHRC) and supported by the National Trust, as well as archaeologists from the University of Cambridge and Allen Environmental Archaeology.

The survey took place inside the Southern Inner Circle. It was undertaken because work by the famous archaeologist and marmalade magnate Alexander Keiller in 1939 demonstrated the existence of a curious angular setting of small standing stones. These were set close to a single huge upright known since the 18th century as the Obelisk. Unfortunately, the outbreak of war left this feature only partially investigated, so the team decided to get to the bottom of this unfinished work.

The geophysical work undertaken in the spring of 2017 revealed a striking and apparently unique square megalithic monument within the circle which may be among the very earliest structures on this remarkable site.

Avebury has been subject of considerable archaeological interest since the 17th century. The discovery of new megaliths inside the monument was therefore a great surprise, pointing to the need for further archaeological investigations of this kind at the site.

It has shown the line of stones that Keiller had identified is one side of a square of megaliths about 30m across and enclosing the Obelisk. Also visible are short lines of former standing stones radiating from this square and connecting with the Southern Inner Circle.

Megalithic circles are well known from the time when Avebury was built during the late Neolithic (3rd millennium BC), but square megalithic settings of this scale and complexity are unheard of.

"This discovery has been almost eighty years in the making but it’s been well worth waiting for. The completion of the work first started by Keiller in the 1930s has revealed an entirely new type of monument at the heart of the world’s largest prehistoric stone circle, using techniques he never dreamt of. And goes to show how much more is still to be revealed at Avebury if we ask the right questions."  - Dr Nick Snashall, National Trust Archaeologist

Using the records from Keiller’s excavations now housed in the museum at Avebury, the team made yet another startling discovery. The square stone structure seems to have  been built to commemorate the site of a Neolithic house. And this in time became the foundation for one of the most important complexes of megalithic sites in the world.

The work is now published and can be found here