Battle of Boquerón Day, also known as Victory at Boquerón Day, is observed in Paraguay every September 29. This public holiday commemorates one of the most significant battles of the Chaco War, which took place between Paraguay and Bolivia from 1932 to 1935 over control of the Chaco Boreal region. The Battle of Boquerón, the war's first major engagement, lasted from September 7 to September 29, 1932, culminating in the surrender of Bolivian troops who had occupied the outpost since July 1932. The Paraguayans launched an all-or-nothing attack after the Bolivians faced severe shortages of water, food, and ammunition. The day is marked by festive events and activities across the country, with all schools, establishments, and businesses closed in observance of the holiday.