WWII
Guerrilla War in Yugoslavia
When the germans invaded the country two guerrilla movements where formed, the communists led by Tito and the nationalists Chetniks who soon joined the germans to fight Tito.
When the germans invaded the Soviet Union a massive wave of attacks begun, and the partisans managed to conquer a great part of the country. The germans tried to destroy them with five offensives, but the stealthy kind of war that the partisans fought prevented their anhilation.
When the war was near to the end the Tito partisans liberated a great part of the country and could mantain an independence from the russians, avoiding the occupation of the country by the Soviet forces.
When the war ended Tito became president of the country.