Battle of Locumba
1880 CE.
Shown on the map at -17.614°, -70.762°.
The Battle of Locumba was a battle of the Tacna and Arica campaign of the War of the Pacific that took place on April 1, 1880, between the Chilean cavalry and the Peruvian garrison at the town.
Text from the Wikipedia article Battle of Locumba, licensed CC BY-SA 4.0.