Together with its allies Italy, Bulgaria and Hungary, Germany invaded Greece and the Kingdom of Yugoslavia on 6 April 1941. The Luftwaffe bombed Belgrade, the Yugoslavian capital, for three days. On 17 May, Yugoslavia surrendered.
Parts of Yugoslavia were added to Germany and its allies. In the west, Italy took the south of Slovenia and a strip along the Adriatic coast. Germany occupied part of Serbia and the north of Slovenia, and Hungary took another part of Slovenia and of Serbia. Bulgaria added Macedonia to its territory.
In a large part of Yugoslavia, a new state was created: The Independent State of Croatia. This new country collaborated with Italy and Germany. It was governed by the fascist Ustaša movement led by Ante Pavelić. This government committed terrible war crimes against Serbs, Jews, and Roma and Sinti.
In 1939, Italy occupied Albania and in October 1940, it attacked Greece from there. In April 1941, when Greece proved to be too strong for Italy, Germany came to Italy’s aid via Yugoslavia and Bulgaria. In May, German paratroopers landed on Crete. After 11 days of heavy fighting, they occupied the entire island and on 1 June 1941, Greece fell.