Sixty-one years ago, on August 6, 1945, as the Enola Gay opened its bomb bay above Hiroshima, most Americans were enjoying a quiet Sunday afternoon. As “Little Boy” fell toward that city of 343,000, Fords and Packards rolled along peaceful country roads half a world away. When a pressure wave shot through Hiroshima with the speed of a bullet, children played stickball in the streets of Dayton and Peoria. And as a blue-white flash cooked the sky above Hiroshima to 18 million degrees Fahrenheit, American families sat down to Sunday roasts.