Riddle Solved

For years researchers have tried to pinpoint exactly where the enormous stones used in the English monument came from--and how they ended up on the Salisbury Plain.

It's long been thought that the iconic monument's outer stones were hauled from a sandstone quarry situated 20 to 30 miles away, National Geographic (NG) reported. The inner stones, however, have presented a tougher question.

Currently, there are two prevailing theories about the inner stones' origins. One is that an ancient glacier simply pushed them near to the site where the monument was erected, according to NG. The other is that they were somehow hauled there by some exceedingly enterprising early humans.

Now a team of researchers say they've located the rocky Welsh hill where some of Stonehenge's inner stones originated. The team -- made up of archaeologists and geologists from several United Kingdom institutions -- claim to have matched a type of stone found at Stonehenge, called a spotted dolerite bluestone, to the Carn Goedog outcrop in Wales, the BBC reported.

Located more than 100 miles from Stonehenge in the Preseli Mountains of Pembrokeshire, the Carn Goedog bluestones (below) were matched with their famous counterparts via chemical analysis, among other scientific techniques.

Interestingly, many researchers may have spent years excavating in the wrong location, The Guardian reported. Since the 1920s, several scientists have been convinced that at least some of Stonehenge's bluestones came from Carn Meini, almost a mile away from Carn Goedog.

"Almost everything we believed 10 years ago about the bluestones has been shown to be partially or completely incorrect," said Rob Ixer, a University College London researcher who was part of the most recent bluestone discovery, according to The Guardian. "We are still in the stages of redress and shall continue to research the bluestones for answers."

The findings, which will be published in an upcoming issue of the Journal of Archaeological Science, come on the heels of the announcement in 2011 that researchers had traced the origin of a different type of Stonehenge bluestone to the Craig Rhos-y-Felin outcrop, near a Pembrokeshire sheep farm. That location is around 3 kilometers from Carn Goedog.