British and Australian forces capture Tobruk in North Africa. The Italian defenders lost 25,000 either killed, wounded or captured.
South African forces cross the border from Kenya and enter Italian Somaliland. The main attack does not begin until 10 February.
German and British forces clash for the first time in the Western Desert.
In Europe Bulgaria joins the Axis. German troops now have direct access from which to invade Yugoslavia and Greece.
Germany invades both Yugoslavia and Greece - Operation Marita.
British forces occupy Addis Ababa in Ethiopia.
Start of the siege of Tobruk after the Germans fail to capture it, the first time advancing German Panzers had been brought to a halt.
The Germans capture Zagreb.
The Royal Yugoslavian Army surrenders, Axis forces annex and occupy the region
The German invasion of Russia - Operation Barbarossa begins. More than 4.5 million troops of the Axis powers invade the USSR along a front stretching almost 3,000 km - the largest military operation in history would also result in the largest casuality rate.
The final phase of the German attack on Russia starts.
The Japanese attack the American Pacific Fleet at Pearl Harbour. In the two hour raid that followed, 18 warships, 188 aircraft and 2,402 servicemen were lost. Luckily, the 3 aircraft carriers of the fleet were all at sea at the time of the attack.
Britain and America declare war on Japan.
Germany declares war on America.