In the 1st century A.D. the Roman Imperial
authorities began to exploit the gold deposits of this region in
north-west Spain, using a technique based on hydraulic power. After two
centuries of working the deposits, the Romans withdrew, leaving a
devastated landscape. Since there was no subsequent industrial activity,
the dramatic traces of this remarkable ancient technology are visible
everywhere as sheer faces in the mountainsides and the vast areas of
tailings, now used for agriculture.