Operation Barbarossa

Operation Barbarossa began on 22 June 1941 when Nazi Germany and its allies invaded the Soviet Union along a vast front from the Baltic to the Black Sea. German planning expected a rapid destruction of Soviet forces, but the campaign combined military conquest with racial occupation policies, mass murder and the opening stages of the Holocaust in the occupied Soviet territories.

German armies advanced hundreds of kilometres and inflicted enormous Soviet losses, but distance, logistics, Soviet mobilisation and increasingly effective resistance slowed the offensive. The failure to take Moscow before winter marked the collapse of the original timetable and turned the invasion into a prolonged war of attrition on the Eastern Front.