22 June 1941 – Operation Barbarossa, the German attack on the Soviet Union, began. Despite the massive preparations spread over many months and the numerous indications Stalin received from many sources, the Soviet forces were taken almost completely by surprise and lost very heavily in the first encounters. The Germans had assembled almost 140 of their own divisions, including 17 Panzer and 13 motorized divisions. These forces were organized in three army groups: Army Group North (Field Marshal Leeb), Army Group Center (Field Marshal Bock) and Army Group South (Field Marshal Rundstedt). Altogether, the Germans deployed over 3,000,000 men, 7100 guns, 3300 tanks, 625,000 horses and 2770 aircraft. The Red Army had 230 divisions (170 of which are in the west, 134 facing the Germans). The Soviet forces were organized into Northwest Front (Kuznetsov), West Front (Pavlov), Southwest Front (Kirpono) and South Front (Tyulenev). They include 24,000 tanks and 8000 aircraft. On the first day of the attack almost everything went the German way. The attack began at 0300 hours with advances on the ground and simultaneous air strikes. The Luftwaffe began its operations very early in order to be over the Soviet bases exactly at zero hour. By noon the Soviet Air Force had lost around 1200 planes. The land battle was equally successful. The panzer spearhead Army Group North advanced 40 miles during the day and Army Group Center captured most of the Bug River bridges intact. Army Group South forces based in Hungary and Romania did not attack during the day.
Napoleon had done the same thing on 24 Jun 1812; both dictators got almost to Moscow before the vastness of the Russian plains and the coldness of the Russian winters drove them back in defeat.