An amazing new study suggests that Stonehenge may have been built far, far away from its current location.

The study, published int he journal Antiquity by researchers at UCL Institute of Archaeology, traces the smaller stones in the 5,000-year-old monument — called bluestones — to two different quarries over in Wales, according to a Huffington Post report.

But that’s not even the most fascinating part. The study finds that the stones were dragged out of the quarries perhaps 500 years before Stonehenge was actually built — and the end location of Wiltshire is 140 miles from these quarries, quite a distance to drag such massive stones.

Professor Mike Parker Pearson, who led the study, says he doesn’t think the builders spent 500 years dragging stones. Instead, he thinks they used the stones in a local monument near the quarries, and then later dragged them to Wiltshire to reassemble into the larger Stonehenge.

The stones are absolutely massive, weighing in at 25 tons for the larger standing stones. These stones are from a closer quarry. Scientists had expected that the smaller bluestones, weighing in at two tons, came from Preseli Hills in Wales but later found that they actually came from Carn Goedog and Craig Rhos-y-felin.

Using radiocarbon dating, the researchers were able to determine that the quarries date to 3400 and 3200 BC. Work on Stonehenge was believed to have started around 2900 BC, according to the report.

Now, researchers are looking for the original monument site. They think they have it narrowed down to a spot located between the quarries.

Stonehenge is a prehistoric monument that is one of the most famous sites in the world, and one of its most enduring mysteries. It is a ring of standing stones set within earthworks that dates to the Neolithic age. Scientists aren’t sure why it was built, but think it could have been an ancient burial ground.