Operation Barbarossa (, named after Frederick I) was the code name for the European Axis's invasion of the Soviet Union during World War II. It began on 22 June 1941. More than 3 million men attacked along the 2,900 km front, making it the largest military invasion in human history. It also involved 600,000 motor vehicles and 750,000 horses. Planning for the operation started in December 1940 and the attack was to start on May 15. Its main objective was to destroy the Soviet military power and included some Nazi ideological goals, as well as to make use of Russia's rich deposits of natural resources, which would be helpful to continue fighting the war against the Allies.