Stonehenge, on Salisbury Plain in southern England, is perhaps the world's best known prehistoric monument, attracting nearly a million visitors a year.
The Stonehenge Riverside Project is a joint initiative run by six English universities with the aim of understanding how the iconic structure relates to the broader landscape and surrounding Stone Age sites.
Recent excavations suggest Durrington Walls closely mirrored Stonehenge, having its own impressive standing circle made of timber and an avenue that linked it to the River Avon.
Stonehenge is aligned with the sunset on the winter solstice, whereas Durrington Walls' large timber circle was aligned with the sunrise on the same day, scientists say.
"Stonehenge isn't a monument in isolation. It is actually one of a pairone in stone, one in timber, with this shared relationship with the river, each with their solstice-aligned avenues and circles," said archaeologist Mike Parker Pearson, leader of the project. More Photos in the News Today's 15 Most Read Stories Free Email Newsletter: Focus on Photography
Photograph by Chris Steele Perkins/Magnum for National Geographic