Humberstone and Santa Laura Saltpeter Works
Humberstone and Santa Laura Saltpeter Works are two former saltpeter refineries located in northern Chile. They were declared a UNESCO World Heritage Site in 2005, as a testament to the historical importance of saltpeter mining in Chile and the culture and social agenda that developed around it in the late 19th century.
Source: Wikipedia — Humberstone and Santa Laura Saltpeter Works (CC BY-SA 4.0)