Thousands of years before the Industrial Revolution, people were mining for metal on an industrial scale
From the summit of the Great Orme, the landscape looks as peaceful as it is striking - all rolling green hills and farmland stretching out to the blue Irish Sea.
But the headland that rises over Llandudno, Wales has a secret, one that lay buried for thousands of years.
More than five miles (8km) of tunnels run beneath the hill's surface.
Spreading across nine different levels and reaching 230 feet (70m) deep, some are so narrow that only children would be small enough to access them.
These are the tunnels of a copper mine: one that was first dug out some 3,800 years ago and that, within a couple of centuries, was the largest in Britain.
"In the 1980s and 1990s, you went from no Bronze Age mines being known in Britain at all, to - suddenly - a lot of small mines being discovered," says Alan Williams of the University of Liverpool's Department of Archaeology in the UK, whose PhD research focuses on the Great Orme.
"And then the star in the crown was basically the Great Orme, which grew to be much bigger than all of the others and, in fact, is one of the biggest in all of Europe. It turned out to be the Stonehenge of copper mining."
In the last year, Williams' analysis of Great Orme copper ore - which he presented at the 2015 Archaeometallurgy in Europe International Conference and which will be published in a forthcoming paper - has confirmed that the mine produced so much high-quality copper for making bronze, some of it wound up as far away as France, Holland and possibly Denmark.
In what he calls a "CSI-type exercise", he has found that Great Orme copper matches that in bronze artefacts found in north-west Europe.
Read the full article here