Peace was gone long before all those innocent people were murdered, and it didn't come back just because the Allies were declared winner. That was how we kept from spending more money and saving the lives of our own troops which i'm not totally opposed to. But chalking something like that up to a winning strategy with just a bunch of casualties of war is a grotesque oversimplification of a rightfully controversial event in history.
In 1945, the United States dropped two atomic bombs on the cities of Hiroshima and Nagasaki. These bombs instantly killed tens of thousands of people and the negative legacy of these attacks have been felt throughout history since. Although this action pushed the modern world into a nuclear age, the unconditional surrender of Japan in August 1945 ended a war that some historians believe could have lasted 6-24 months longer if the USA decided to invade the island nation-state. This is why the dropping of the atomic bombs on Japan was a necessary action to secure world peace.