The Chaco War 1932-35 pitted Bolivia against Paraguay for control over the Northern Chaco region which was thought to contain oil deposits. Paraguay started with a small army of 3000 poorly equipped men which they quickly raised to 60,000 men. Bolivia hired German General von Kundt to command their army but the Paraguayan army eventually captured the Bolivian HQ and over 30,000 Bolivian prisoners. A truce on June 12, 1935 ended the fighting. The treaty of Buenos Aires, July 21, 1938, gave Paraguay 75% of the Chaco region and Bolivia an outlet to the South Atlantic via the Paraguay River. Everyone got something so both sides issued a medal and acted like victors. Bolivia issued the multicolor one on the left and Paraguay the bronze cross on the right.
If as a medal collector you want a real challenge start collecting South American medals. The only thing harder to find than the medals themselves are any references about them. If you read Spanish maybe you will have an easier time finding good information than someone who doesn’t.