Saltpeter (or sodium nitrate) was used for a while as an explosive, and as such was exported to Peru. It could be found in the Northern pampas, from Tarapaca to Antofagasta. During the first half of 19th century its fertilizing qualities were discovered, and so began the shipments to the US and Europe. Around the year 1839 the international demand was so big that motivated the arrival of all kinds of investors (Chilean and foreign). The land was then part of Peru and Bolivia's territory. The amount of profits involved was one of the main reasons for what was then called the Pacific War, after which (1884) the territory would be annexed to Chile.

The production and export of saltpeter became a key element for international agriculture development and for Chile' economic, social and political progress as well. What was then created around it was a large commercial and production system, and also a way of life and culture that would come to distinguish the area, and which combined the wealth of a cosmopolitan city (so was back then Iquique) with the strengthening of a social movement, borne by the sweat of workers who started fighting for their rights. It's an identity marked by the tenacity, effort, enterprising spirit and creativity that they needed to develop in order to live in such a hostile and solitary environment.

Humberstone was built in 1872 under the name of La Palma. It became the region's most important office, but -the same as Santa Laura- it had to stop working around the time of the Big Depression. The activities were resumed in 1933, this time under the name Santiago Humberstone, as an homage to the British chemist who adapted the nitrate industry to a new elaboration system called Schanks -the one used in Humberstone and Santa Laura.

Its biggest growth happened between the years of 1933 and 1940, when more than 3,700 people came to live in the zone. A big crisis forced its closing along with the ones then known as the Nebraska Group (Santa Laura, Nebrasca, Peña Chica and Keryma), all of which were auctioned in 1962 and ended up in private hands.

Santa Laura was built in 1872. By 1920, 450 people were living in it. Both offices are now open to visitors.