The Copper Mine in Falun, the Great Pit

Falun Mine (Swedish: Falu Gruva) was a mine in Falun, Sweden, that operated for a millennium from the 10th century to 1992. It produced as much as two thirds of Europe's copper needs^[1] and helped fund many of Sweden's wars in the 17th century. Technological developments at the mine had a profound influence on mining globally for two centuries.^[2] Since 2001 it has been designated a UNESCO world heritage site as well as a museum.

• http://en.wikipedia.org/wiki/Great Copper Mountain