Anglesey, a large island off the north-west coast of Wales, has seen copper mining since ancient times. But it was not until the late 1760s that miners discovered the sheer extent of the island’s mineral wealth — especially at a place called Parys Mountain, not far from the island’s north-eastern coast. The flood of copper that issued forth from the mountain in the late eighteenth century drove many of Cornwall’s copper mines out of business. And it prompted small towns and villages like Swansea, Macclesfield, St Helens and Warrington — not too far along the coast from Anglesey, but with plenty of nearby coal for fuel — to swell into cities devoted to smelting the mountain’s ore. Cheap copper made it possible for the Royal Navy to sheathe the hulls of its ships against the wood-hungry Caribbean teredo worm. And it fed the extensive brass manufactures of the West Midlands.