The Humberstone and Santa Laura Saltpeter Works in northern Chile are part of an abandoned mining town that was at its peak during the early 19th century.
Miners in the town harvested saltpeter, which was used to produce sodium nitrate fertilizer. This industry was booming in the town until synthetic nitrate was invented during WWI, rendering Humberstone and Santa Laura obsolete.
As a result, the mining town was shut down and abandoned, although many of the buildings still stand today and are part of a UNESCO World Heritage Site.