The mercury mines of Almaden (Spain) and Idrija (Slovenia) recently included in UNESCO's Heritage List

The property includes the mining sites of Almadén, where mercury (quicksilver) has been extracted since Antiquity, and Idrija, where mercury was first found in 1490 A.D. The Spanish property includes buildings relating to its mining history, including Retamar Castle, religious buildings and traditional dwellings. The site in Idrija notably features mercury stores and infrastructure, as well as miners’ living quarters, and a miners’ theatre. The sites bear testimony to the intercontinental trade in mercury which generated important exchanges between Europe and America over the centuries. The two sites represent the two largest mercury mines in the world and were operational until recent times. (Source: UNESCO)

More information:
http://whc.unesco.org/en/list/1313/

Mine shaft in Idrija. Picture Luis Jorda, 2002