Las Médulas, located near the town of Ponferrada in León province, Spain, used to be the most important gold mine in the Roman Empire. Las Médulas Cultural Landscape is listed by the UNESCO as one of the World Heritage Sites. The spectacular landscape of Las Médulas resulted from the Ruina Montium, a Roman mining technique described by Pliny the Elder consisting in the perforation of the mountain and latter irruption of great quantities of water that literally pulled the mountain down, a precedent of Californian hydraulic mining.
