Siege of Uruguaiana
1865 CE.
Shown on the map at -29.755°, -57.088°.
The siege of Uruguaiana was an engagement in the Paraguayan War that began in late August 1865, and ended on 18 September that year when the Paraguayans were forced to surrender due to low food supplies. Paraguayan forces surrendered in spite of President López's order to the Paraguayan commander, Colonel Estigarribia, not to do so. After the allied victory at Uruguaiana, Lopéz withdrew his army from Argentina and Brazil.
Text from the Wikipedia article Siege of Uruguaiana, licensed CC BY-SA 4.0.