1945 In July, the United States successfully tested and exploded the world's first yzd, and mankind entered the era of nuclear weapons. Oppenheimer, the main scientist involved in research and development, expressed his complicated feelings with Indian poetry: "I am becoming death, the destroyer of the world."

After World War II, Einstein was asked what weapons would be used in World War III. Einstein said, "I don't know what weapons were used in World War III, but I know that the weapons used in World War IV were stones." It implies that nuclear war will inevitably bring mankind back to the wild.