Chaco War

The Chaco War was fought from 1932 to 1935 between Bolivia and Paraguay for control of the northern Gran Chaco, a semi-arid region thought to hold petroleum. It is also called the War of Thirst because of the dry terrain. It was the first war in South America in which modern weapons such as machine guns, armoured fighting vehicles and airplanes were used, and it was the bloodiest South American war of the twentieth century, with roughly two percent of Bolivians and three percent of Paraguayans killed. Both countries were landlocked and struggled to move arms and supplies through their neighbours. Bolivia had the larger and better equipped army, but trade problems and poor internal communications turned the war against it. A peace conference in Buenos Aires in July 1938 awarded about three quarters of the Gran Chaco to Paraguay.