It took scientists nine months, but they are now sure the inner stones of Stonehenge came from Pembrokeshire, Wales, about 160 miles from the Stonehenge site.
As the BBC reports, Robert Ixer of the University of Leicester and Richard Bevins of the National Museum of Wales pinpointed the source to within 230 feet and did so by "detailing the mineral content and the textural relationships within the rock, a process known as petrography." They compared the make up of the Stonehenge stones to that of the Pembrokeshire ones and "found that 99% of the samples could be matched to rocks found in this particular set of outcrops."
Wired adds that this answers that question definitively, but there's another big mystery to be solved:
"The question remains though, as to how neolithic people transported huge chunks of rock from Wales to Wiltshire, some 5,000 years ago. Some historians reckon that these stone age builders quarried the stones in Pembrokeshire and brought them over to England, while others argue that giant glacial shifts moved the stones, hundreds of thousands of years earlier.
"Ixer and Bevins hope that by finding the exact source for some of the monument's stones, they will be able to discover new clues as to when and how they made their 160 mile journey."
The Independent digs fairly deep into the findings. They also explore the small mysteries: If the stones were moved by people, this must have believed they came from a pretty special place:
"They may have regarded [the Pembrokeshire stones] as extremely important - and could even have seen them as possessing supernatural powers.
"The newly discovered source is also significant because of its location. It lies on low ground to the north of the Preseli Mountains. This would have made transport to Wiltshire much more difficult than it would have been for other Pembrokeshire rocks used in Stonehenge and, known to have come from the High Preseli several miles to the south.
"Transporting the north Pembrokeshire stones by sea would have required sailing round St. David's Head, a particularly difficult and dangerous route for a Neolithic boat. Alternatively the prehistoric quarrymen and their colleagues would have had to haul the stones over the top of the nearby Preseli Mountains."