Operation Barbarossa — Germany Invades the Soviet Union

Germany launched the largest land invasion in history, deploying 3.8 million Axis troops along a 2,900-km front against the Soviet Union. The surprise attack initially routed the Red Army, capturing millions of prisoners and vast territory. However, Hitler's decision to divide forces among three army groups — Leningrad, Moscow, and Kyiv — dispersed strength and slowed the advance before Moscow.