In the world's driest desert, the Atacama, three countries clashed for control of a resource more valuable than gold: saltpetre, essential for producing gunpowder. From there, in 1879, the war between Chile, Peru, and Bolivia began, a conflict that in just a few years reshaped the geography of South America.
It all started with a decision by the Bolivian government. In 1878, Bolivia imposed a new tax on a Chilean company extracting saltpetre in Antofagasta, in violation of a previous agreement prohibiting tax increases. Chile protested and requested arbitration, but Bolivia refused and seized the mines. At that point, the crisis became a military one. On February 14, 1879, Chilean troops occupied Antofagasta, a Bolivian territory largely inhabited by Chileans. Bolivia declared war, and Peru, linked to La Paz by a secret alliance, entered the conflict shortly thereafter.

A local dispute escalated into a regional war. Control of the Pacific Ocean was crucial, as without it, it was impossible to supply armies in the desert. After months of naval clashes, Chile gained maritime dominance, thereby securing the key to winning the war. From that moment, the war shifted to land, and Chilean troops advanced into the desert, defeating the allied armies. In 1880, after the Battle of Tacna, Bolivia effectively withdrew from the conflict, leaving Peru alone. Chile thus continued its offensive, reaching as far as Lima, the Peruvian capital, which was occupied in 1881. Even after the city's fall, resistance continued in the interior through guerrilla warfare. It was a long and exhausting war, and it did not end until 1884.
Chile emerged victorious from the war, Bolivia lost access to the sea, and Peru ceded resource-rich territories. Control of saltpetre passed to Chile, which reaped enormous economic benefits. For Bolivia, the loss of its access to the sea became a historical wound that is still open. For Peru, it was a traumatic defeat that affected national politics for decades. For Chile, more organised and stable, which managed to assert itself over two more fragile and divided countries, it marked the beginning of a phase of growth as a regional power.