World War II in Yugoslavia

World War II in the Kingdom of Yugoslavia began on 6 April 1941, when the country was invaded and swiftly conquered by Axis forces and partitioned among Germany, Italy, Hungary, Bulgaria and their client regimes. Shortly after Germany attacked the USSR on 22 June 1941, the Comintern issued directives to all communist parties to come to the Soviet Union's aid, following which the communist-led Yugoslav Partisans launched a guerrilla liberation war fighting against the Axis forces and their locally established puppet regimes, including the Axis-allied Independent State of Croatia (NDH) and the Government of National Salvation in the German-occupied territory of Serbia.

Source: Wikipedia — World War II in Yugoslavia (CC BY-SA 4.0)