Place to see: Mina de Sao Domingos, Mértola, Portugal

About this place:

The Romans have been mining here for gold and silver for about 400 years and mining stopped here when the Romans left.
In 1855 mining was resumed, as the international demand for copper grew during the Industrial Revolution. The mining concession was leased for 50 years to an English mining company, Mason & Barry.
They switched from tunnel mining to open pit mining. Copper ore was the main product of the mine; in addition, pyrite was mined as a source of sulphur.
The mine was closed in 1966.