From Business Insider:

The origin story of Stonehenge has baffled archaeologists for centuries.

The mysterious monument, erected in two waves of flurried construction 5,000 and 4,500 years ago, on the UK’s Salisbury Plain features two distinct types of stone slabs in half circles.

Researchers traced one stone type, the smaller bluestones, to a site in Wales. But the origin of Stonehenge’s 30-foot (9-meter) sandstone boulders, called sarsens, remained an unsolved puzzle until now. 

According to a study published Wednesday in the journal Science Advances, Stonehenge’s builders dragged most of these 50,000-pound (22,700-kilogram) sarsens from a woodland area in Wiltshire.

The area, called West Woods, is more than 15 miles (25 kilometers) from the monument — “which is insane really if you think about it,” David Nash, the lead author of the study, told Business Insider.

He added, “Our results suggest that most of the sarsens at Stonehenge share a common chemistry, which is why we’re saying they come from the same area.”

The findings could help archaeologists figure out how the builders transported the giant stones south.

More at the link.