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 Pampas, 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 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.