Deep inside an ice cap in the Peruvian Andes, scientists have traced air pollution from 16th-century Spanish silver mines. In an announcement made on Monday, scientists said the pollution appeared to have originated from what is now called Bolivia, located hundreds of miles away at the Potosí mountaintop silver mines. The imprint of metal-rich smog was actually discovered in Peru.
Designated as a UNESCO World Heritage site, Potosí is located at an altitude of about 13,120 feet. Efforts were being diligently made by the Inca people to extract and refine silver from Potosí for generations before the Spanish arrived.