The Newsreel - Hitler Blunder in the Balkans 1941

The Balkan Campaign of World War II began with the Italian invasion of Greece on 28 October 1940. In the early months of 1941, Italy's offensive had stalled and a Greek counter-offensive pushed into Albania. Germany sought, by deploying troops to Romania and Bulgaria, to aid Italy by attacking Greece from the east; while the British landed troops and aircraft to shore up Greek defences. A coup d'état in Yugoslavia on 27 March caused Hitler to order the conquest of that country.

The invasion of Yugoslavia by Germany and Italy began on 6 April, simultaneously with the new Battle of Greece. On 11 April, Hungary joined the invasion. By 17 April the Yugoslavs had signed an armistice and by 30 April all of mainland Greece was under German or Italian control. On 20 May Germany invaded Crete by air and by 1 June all remaining Greek and British forces on the island had surrendered. Although it had not participated in the attacks in April, Bulgaria occupied parts of both Yugoslavia and Greece shortly thereafter for the remainder of the war in the Balkans.
The invasion of Yugoslavia (also known as "Operation 25") began on 6 April 1941 and ended with the unconditional surrender of the Royal Yugoslav Army on 17 April. The invading Axis powers (Nazi Germany, Fascist Italy, and Hungary) occupied and dismembered the Kingdom of Yugoslavia. By cobbling together Bosnia and Herzegovina, some parts of Croatia, and Syrmia, the "Independent State of Croatia" (Nezavisna Država Hrvatska, NDH) was created by Germany and Italy. In some of the territory of the former Kingdom of Serbia and the Banat, the German-occupied Territory of the Military Commander in Serbia, the Germans appointed a puppet government, the Government of National Salvation led by Milan Nedić. Montenegro remained under Italian occupation, and Bulgaria was permitted to annex eastern areas of Yugoslavia, including most of modern-day Macedonia.