The Bloodiest War in the Americas

On Dec. 13, 1864, the small landlocked but strategically positioned country of Paraguay declared war on the Brazilian Empire. The ensuing conflict became the worst in South American history, leaving nearly 90 percent of Paraguayan men of fighting age dead.

The Paraguayan War laid the foundation of contemporary South America's geopolitical divisions. The conflict emerged as a result of Paraguay's centrality in the Platine River Basin and its position in the heartland of South America. Their underlying geopolitical imperatives — the need to secure access to key waterways providing trade routes and outlets to the Atlantic — forced the national interests of Argentina, Brazil, Paraguay and Uruguay to collide in the worst armed conflict in South America's history. Today, 150 years later, the impact of the war still resonates, dominating and defining the nature of regional politics.