Found: A Hidden Stone Square Inside the World’s Largest Megalithic Stone Circles

The Neolithic monument at Avebury may be less well known than Stonehenge, but it is fantastic. Sprawling over an area of about 20 acres, there’s an outer ring, 1,000 yards in circumference, of stones stood on end—originally, they may have been 98 standing stones. Insider, there are two more, smaller stone circles.

Some archaeologists have speculated that, when this monument was built, more than 5,000 years ago, its creators began with the outer circle. But now a team from the University of Leicester has mapped a hidden stone square in the center of the monument, which they believe was built even earlier, The Guardian reports.

The team used radar technology to find the position of the stones in the square, some of which were moved or destroyed in the 17th or 18th century. They found a shape with sides about 32 yards long. Most intriguingly, this square was centered around a mysterious, long-gone wooden structure.

When “archaeologist and marmalade magnate” Alexander Keiller worked on this site in 1939, he found post holes and other evidence that a wooden structure had once stood at the center of the stone circle. He thought this was probably a medieval shed of some sort.

But the Leicester team believes it may have been much, much older. Team leader Mark Gillings told The Guardian, “Our working interpretation is that the house is the first thing. It falls into ruin but they’re still remembering and respecting it. They put a square around it about 3000 BC and then the circles. It’s like ripples on a pond coming out from the house.”

No one knows exactly what this wooden structure would have been used for. Perhaps it was the dwelling of an important person, a meeting house, or a ritual space. The stone square itself is “highly unusual,” The Guardian says—a new clue in the mysterious ritual life of England’s past.