Eliza Lynch, the mistress of one of his successors, was forced to dig that successor's grave.
The Nor Yungas Road, renowned for its danger, was built by POWs from this country. One leader of this country delayed a shipment from England until he could learn English and read the ship's books, which he did for all incoming ships. That leader (*)  pursued a policy of forced interracial marriage. Eliza Lynch, the mistress of one of his successors, was forced to dig that successor's grave. This nation's Children's Day falls on the anniversary of a battle at which it used child soldiers with painted beards and sticks to fight modern infantry regiments during a war in which they lost the Siege of Humaita. For ten points, name this country that lost 2⁄3 of its male population in the War of the Triple Alliance.
The Nor Yungas Road, renowned for its danger, was built by POWs from this country.
Paraguay