Germany and the Soviet Union sign the Nazi-Soviet Non-Aggression Pact
The Japanese launch a sneak attack on Pearl Harbor, Hawaii. This had a major impact on the course events of World War II. It served the purpose of getting direct involvement of the USA in the war. USA officially entered war on December 8, 1941.
The Battle was a turning point in the North African campaign. The Second Battle of El Alamein pushed all German forces out of North Africa and opened up the way for the Invasion of Sicily and Italy. It was a major defeat for Rommel's Desert Army. The German army began to realize that they could not win without more supplies.
Midway is considered the turning point of the War in the Pacific.
It marked the start of the Allies' invasion of Western Europe and paved the way for Allied victory. It was a key turning point and marked the beginning of the end of Hitler's reign.