Humberstone And Santa Laura Saltpeter Works, Atacama Desert, Tarapacá, Chile

Both works were abandoned in 1960 after the rapid decline that caused COSATAN to disappear in 1958. In 1970, after becoming ghost towns, they were declared national monuments and opened to tourism. In 2005 they were declared a World Heritage Site by UNESCO.
Description from UNESCO World Heritage Site web site
Humberstone and Santa Laura works contain over 200 former saltpeter works where workers from Chile, Peru and Bolivia lived in company towns and forged a distinctive communal pampinos culture. That culture is manifest in their rich language, creativity, and solidarity, and, above all, in their pioneering struggle for social justice, which had a profound impact on social history. Situated in the remote desert Pampa, one of the driest deserts on earth, thousands of pampinos lived and worked in this hostile environment, for over 60 years, from 1880, to process the largest deposit of saltpeter in the world, producing the fertilizer sodium nitrate that was to transform agricultural lands in North and South America, and in Europe, and produce great wealth for Chile. Because of the vulnerability of the structures and because of the impact of a recent earthquake, the site was also placed on the List of World Heritage in Danger, to help mobilize resources for its conservation.