The tall, bluestone pillars of Stonehenge in England are an iconic mystery, but what lies beneath is also “astonishing,” a recent survey of the surrounding land found.

While the final results won’t be presented until next month at the British Science Festival, the Stonehenge Hidden Landscape Project gave Ed Caesar for Smithsonian Magazine a bit of a preview.

Researchers with the Ludwig Boltzmann Institute for Archaeological Prospection and Virtual Archaeology and the University of Birmingham conducted the “first detailed underground survey” of the area around Stonehenge finding that there’s more to the ancient structure than what’s above the surface.

Researchers used high-tech equipment to sense possible structures underneath the ground around Stonehenge. (Image source: Ludwig Boltzmann Institute for Archaeological Prospection and Virtual Archaeology)

Researchers used high-tech equipment to sense possible structures underneath the ground around Stonehenge. (Image source: Ludwig Boltzmann Institute for Archaeological Prospection and Virtual Archaeology)

Smithsonian Magazine reported that more than 15 possible unknown or poorly understood monuments underneath the soil in a configuration that would make Stonehenge’s speculated area larger than previously though.

“There was sort of this idea that Stonehenge sat in the middle and around it was effectively an area where people were probably excluded,” Vince Gaffney told Caesar, “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. Of course that sort of analysis depends on not knowing what’s actually in the area around Stonehenge itself. It was terra incognita, really.”

“The perceived wisdom was driven by the monuments we knew about,” Gaffney told the magazine. “We’ve put in the data between the monuments.”

The possible structures weren’t found by actual digging but with high-tech ground surveying equipment that could look below the surface. According to the institute’s webpage about the four-year project (via an unofficial translation), the team used a motorized magnetometer, ground-penetrating radar and 3-D laser scanners.

Photo credit: Shutterstock

Photo credit: Shutterstock

The possible structures, Gaffney said, could give clues as to the purpose of the Stonehenge Cursus, which is a two-mile-long strip that starts north of the round Stonehenge setup and runs from east to west.

Gaffney and others emphasized though that these findings are not confirmed to be related to Stonehenge per se because no actual digging has taken place.

“Until you dig holes, you just don’t know what you’ve got,” Parker Pearson with the University College London told Caesar. “What date it is, how significant it is. [There are] extraordinary new features coming up, and we’re thinking well, what are they?”

For more details regarding this findings, check out Caesar’s full post in Smithsonian Magazine.