World War Two
The accepted view is that the war began in earnest on 1939-09-01 with the raid of Poland by Nazi Germany, and concluded on 1945-09-02 with the official surrender of the last Axis force, Japan. However, in Europe, the war had concluded earlier with the unconditional surrender of Germany on 1945-05-08.
One interesting study documents how the strategic bombing of Germany was documented in popular American journals.
Each theater, the European and the Pacific, were marked by an occurrence. In Europe, Hitler's Germany was intent on murdering every Jew in Europe. Six million perished. The defeat of Nazi Germany, however, led to an international movement to provide the displaced Jews with a homeland, and in 1948 the State of Israel was created in the Levant. Hitler's strategy backfired; instead of eradicating the Jews, his demonic policies led to the first Jewish state since Biblical times and a guarantee that the Jewish people would survive.
Other ethnic groups suffered mightily from the Aryan view of self-supremacy. Twenty million Russians, largely civilians, died in World War II. The Germans also murdered homosexuals, gypsies, clerics, and other considered inferior to the German people.
In the Pacific theater, the decision not to invade Japan led to the unleashing of the atomic bomb on Hiroshima and, after Japan remained steadfast in its refusal to surrender, Nagasaki. The atomic age began when the Japanese refused to recognize the inevitable.