The Roman Empire mined gold in Spain by digging shafts and tunnels deep into the mountains. This yielded gold, but not as much as what came after. At the same time, they built aqueducts and diverted mountain runoff water to the hilltops. When they had enough water, they would flood the shafts and tunnels until the pressure split the mountain open! The fallen rock could then be sifted for gold. The technique was called ruina montium, or the wrecking of mountains. The tons of gold they recovered ended up stamped with Caesar's likeness, and the mountains still show the scars 2,000 years later.
The mountains shown above are Las Médulas in northwestern Spain, where the mining technique and the aqueducts still remain. It is a UNESCO World Heritage Site. Read about the wrecking of the mountains and what it left behind, with plenty of pictures, at Amusing Planet.
(Image credit: Udri/CC BY-NC-SA 2.0
Commenting on Neatorama will earn you NeatoPoints!