For 10 points, name this 1930's war in which Paraguay defeated Bolivia to gain control of the namesake region.
Near the end of this war, the president of the losing country was overthrown by his generals while visiting their headquarters, causing him to remark it was their only successful military maneuver of the war. One side in this war employed White Russians Ivan Belaieff and Nicholas Ern as fortification and cartography specialists. The numerous casualties due to lack of water have caused this conflict to be known as the (*) "War of Thirst." The losing side in this war unsuccessfully utilized Vickers tanks under the command of Hans Kundt, whose officers could not communicate with their mostly native troops. That side, under President Daniel Salamanca, was desperate to obtain ocean access after losing the War of the Pacific. For 10 points, name this 1930's war in which Paraguay defeated Bolivia to gain control of the namesake region.
Near the end of this war, the president of the losing country was overthrown by his generals while visiting their headquarters, causing him to remark it was their only successful military maneuver of the war.
{Gran Chaco} War [accept La {Guerra} de la {Sed} or The {War} of {Thirst} until mentioned]