World War II was a world-spanning war, considered to have begun when Nazi Germany invaded Poland in September of 1939. The nations of the world, including all major powers, effectively became organized into either of two groups: the Axis or the Allies. World War II led to over 70 million casualties (civilian and military) and resulted in an Eastern Bloc being set up over Eastern Europe.
As mentioned above, WWII is commonly referred as to starting on September 1, 1939 with the German invasion of Poland. On December 7th, 1941, Japanese forces bombed Pearl Harbor which in turn brought the United States into an ever expanding war.
BeginningAlthough universally the war began in 1939 with the Invasion of Poland, some historians have argued that the war stated in 1937 with the Second Sino-Japanese War or even 1931. This wiki uses the "universal dating system", in which the war started 1 September 1939 and ended 2 September 1945.
In 1945, the Germans surrendered shortly after the suicide of Adolf Hitler and the encirclement of Berlin by the Red Army. Many Nazi war criminals were taken as prisoners or were executed. At the same time, during Operation Paperclip, German scientists and engineers were being secretly rushed out of the country to the United States and Great Britain. Some of these scientists include the famed Wernher Von Braun. Soon after the collapse of Germany, the United States dropped the first Atom bombs on the Japanese cities of Hiroshima and Nagasaki. When the Japanese government still stalled negotiations, over 1,000 Allied bombers and fighters were dispatched for the final blow to Japan. The official end of the war is commonly referred to as September 2, 1945, with the official Japanese surrender on the USS Missouri.