Is Stonehenge a second-hand wonder? New research suggests that many of its stones were probably taken from other monuments.
Scientists excavated two quarries in Wales and found rocks that matched the "bluestones" at Stonehenge. That led them to conclude that the bluestones were previously used in other monuments before being carried nearly 140 miles to Stonehenge's current site in Wiltshire, England.
Built around 5,000 years ago, Stonehenge is made from large sandstone monoliths and smaller bluestones, which, measuring up to 2 tons and 8 feet tall, are still pretty large.
"Stonehenge was a Welsh monument from its very beginning," Mike Parker Pearson, an archaeologist from the UCL Institute of Archaeology, said in a statement. He led the study, which was published Monday in the journal Antiquity.
"If we can find the original monument in Wales from which it was built, we will finally be able to solve the mystery of why Stonehenge was built and why some of its stones were brought so far."
Related: 'Stonehenge Is Not Alone': More Monuments Detected Nearby
Using radiocarbon dating, Pearson and his team analyzed samples from two rocky outcrops, known as Goedog and Craig Rhos-y-felin, in the Preseli hills in Pembrokeshire in southwest Wales. The bluestones appear to have been quarried around 4,000 years ago.