Battle of Acosta Ñu

In 1869 during the Paraguayan War 90% of the male population of Paraguay had already died at the hands of the invading Brazilian, Argentinian and Uruguayan armies. The Paraguayans went to make a last stand at Campo Grande but they didn't have enough men so they assembled a 6,000 strong army composed mainly by children. The children anywhere from 6 to 15 painted beards on their faces to look like grown men. A 20,000 strong Brazilian army charged and slaughtered them and by the end of the day, there were 3,500 Paraguayan children dead and 46 Brazilian deaths. To this day on August 16th, the day of the battle, Paraguay celebrates Children's Day.