Stonehenge, perhaps the world's most famous neolithic monument, is like an iceberg, with unsuspected monuments now revealed beneath the surface. The discoveries have expanded the range of potential astronomical uses to which the builders could have used the mighty structure.

It has taken four years for The Stonehenge Hidden Landscape Project to reveal 15 potential henges, pits and barrows using ground penetrating radar and 3D laser scanning. Some of these objects were known to exist beforehand, but little was known about them, while others were completely unexpected.

University of Birmingham archaeologist Professor Vince Gaffney didn't just study the area within the circle and immediate surrounds. He surveyed 10km2 around the standing stones.

“There was sort of this idea that Stonehenge sat in the middle and around it was effectively an area where people were probably excluded,” Gaffney told The Smithsonian, “a ring of the dead around a special area—to which few people might ever have been admitted....Perhaps there were priests, big men, whatever they were, inside Stonehenge having processions up the Avenue, doing...something extremely mysterious.”



Heritage UK. Stonehenge retains many hidden secrets

Perhaps it is not surprising that the might henge was actually the center of plenty of activity. The 4-8 tonne bluestones were brought from North Wales, almost 300km away, by methods unknown; an astonishing feat in any circumstances and particularly so if most people were excluded from their destination.