Operation Barbarossa beginning 22 June 1941, was the code name for Germany’s invasion of the Soviet Union during World War II. Over four million soldiers of the Axis powers invaded the USSR along a 2,900 km (1,800 mi) front, the largest invasion in the history of warfare. In addition to troops, Barbarossa used 600,000 motor vehicles and 750,000 horses. The ambitious operation was driven by Adolf Hitler’s persistent desire to conquer the Soviet territories as embodied in Generalplan Ost. It marked the beginning of the pivotal phase in deciding the victors of the war. The German invasion of the Soviet Union caused a high rate of fatalities: 95% of all German Army casualties that occurred from 1941 to 1944, and 65% of all Allied military casualties from the entire war.
Operation Barbarossa was named after Frederick Barbarossa, the medieval Holy Roman Emperor. The invasion was authorized by Hitler on 18 December 1940 (Directive No. 21) for a start date of 15 May 1941, but this would not be met, and instead the invasion began on 22 June 1941. Tactically, the Germans won resounding victories and occupied some of the most important economic areas of the Soviet Union, mainly in Ukraine. Despite these successes, the German offensive stalled on the outskirts of Moscow and was then pushed back by a Soviet counter offensive without ever having taken the city. The Germans could never again mount a simultaneous offensive along the entire strategic Soviet–German front. The Red Army repelled the Wehrmacht’s strongest blow, and Adolf Hitler did not achieve the expected victory, but the Soviet Union’s situation remained dire.
Operation Barbarossa’s failure led to Hitler’s demands for further operations inside the USSR, all of which eventually failed, such as continuing the Siege of Leningrad, Operation Nordlicht, and Operation Blue, among other battles on occupied Soviet territory.
Operation Barbarossa was the largest military operation in history in both manpower and casualties. Its failure was a turning point in the Third Reich’s fortunes. Most importantly, Operation Barbarossa opened up the Eastern Front, to which more forces were committed than in any other theater of war in world history. Regions covered by the operation became the site of some of the largest battles, deadliest atrocities, highest casualties, and most horrific conditions for Soviets and Germans alike—all of which influenced the course of both World War II and 20th-century history. The German forces captured over three million Soviet POWs in 1941, who were not granted the protection stipulated in the Geneva Conventions. Most of them never returned alive. Germany deliberately starved the prisoners to death as part of its “Hunger Plan”, i.e., the program to reduce the Eastern European population.