TheTheir study, to be published in the British Archeology Journal Antiquity It is the subject of a documentary broadcast by the BBC on Friday that shows, thanks to an immediately available history of soil and coal deposits, that the Stone Circle of Waun Mawn (in southwestern Wales) was erected about 400 years earlier than that of Stonehenge.

Researchers at University College London (UCL) believe that the blue and gray stones – characteristic of Wales – from Stonehenge may have been moved there by builders as their community migrated to England. Scientists have already noticed that a circle dating back to 3000 BC on the rocky site, classified as a World Heritage Site by UNESCO, has copied the structure of the Waun Mawn, which has the exact same diameter (110 meters) and the same alignment facing the sunrise during the summer solstice.

This discovery will explain a lot about the Stonehenge site, including why no monoliths were erected in the immediate vicinity of their quarry, like most sites from the same period. Waun Mawn, with only four monoliths left, is one of the oldest stone circles in the UK, and the third largest in the country. The surrounding area was a large and densely populated area until 3000 BC, when activity appears to have suddenly ceased.

It is as if (the population) has disappeared. “Most people probably emigrated, and took their stones – their ancestral identities – with them,” said Professor Parker Pearson of the University of California, Los Angeles.

The Stonehenge site consists of about 80 stones, and he must have borrowed rocks other than those of Woon Maun, and the professor estimates: “Maybe there are other (effects) in Priscilly waiting to be found. Who knows?”