On June 22, 1941, Nazi Germany launched Operation Barbarossa, invading the Soviet Union along an 1,800-mile front stretching from the Baltic Sea to the Black Sea. More than 3 million Axis troops, supported by approximately 3,000 tanks and 2,500 aircraft, advanced into Soviet territory. The attack caught the Red Army unprepared, and German forces penetrated up to 300 miles within days. The campaign stalled by Soviet resistance, logistical strain, and winter conditions, and Germany's failure to achieve its objectives shifted the war's momentum on the Eastern Front.