The War of Paraguay, which took place between 1864 and 1870, was one of the most brutal wars in the history of South America. It involved the Triple Alliance, composed of Argentina, Brazil, and Uruguay, against Paraguay. Brazil entered the war due to the seizure of the ship Marquês de Olinda on the Paraguay River and the invasion of Paraguayan troops in Mato Grosso. Argentina also declared war on Paraguay after the Paraguayan invasion in the Corrientes region.

The paraguayan cannon "El Cristiano"