On September 1st, 1939, Germany invaded Poland and the Western democracies decided that their policies of appeasement had been failing. On September 3rd of 1939, France and Britain had declared war on Germany, which in turn had started World War II.
U.S. Defeats Japanese in Battle of Midway
In July of 1940, Nazi forces had commenced an air attack on Britain which lasted until the near end of October of 1940. These bombings had not broken British morale as they proved to be far more resilient than Hitler thought.
On December 7th, 1941, Japanese aircraft had surprised an American fleet in Pearl Harbor with bombings, ending the U.S.' neutrality and causing them to side with the Allies.
Hiroshima and Nagasaki
In June of 1942, the United States defeats the Japanese in the Battle of Midway within the Pacific Ocean war. This battle had been a decisive turning point as the Japanese had controlled much of the Pacific.
Following Adolf Hitler's apparent suicide, on May 7th, 1945, Germany surrendered to the Allied forces. This victory secured most of Europe, enabling the Allies to finish the war with Japan.
On August 6th of 1945, the United States the atomic bomb on Hiroshima, devastating the Japanese. On August 9th, the United States dropped another bomb on Nagasaki. These bombings not only left Japan in horror, but the bombings had also showed the world, the Soviet Union in particular, the power of the atomic bomb.