Battle of Huaqui
1811 CE.
Shown on the map at -16.629°, -68.919°.
The Battle of Huaqui or Battle of Guaqui-modern spelling- (in some sources also called Yuraicoragua or Battle of Desaguadero), was a battle on June 20, 1811, between the Primera Junta's (Buenos Aires) revolutionary troops and the royalist troops of the Viceroyalty of Peru on the border between Upper Peru, (present-day Bolivia), resulting in a comprehensive defeat of the revolutionary armies.
Text from the Wikipedia article Battle of Huaqui, licensed CC BY-SA 4.0.