The image, taken in 1945, shows physicist Harold Agnew of the Manhattan Project - a research group of US, UK and Canadian scientists formed to construct a nuclear weapon during World War II. In the photo, Harold is gleefully holding the plutonium core of the 'Fat Man' - one of the world's most deadly weapons, a 14 pound mechanism responsible for 80,000 deaths. The heart of the 'Fat Man' atomic bomb was detonated over the Japanese city of Nagasaki on August 9, 1945. Three days after US deployed the nuclear bomb, Japan surrendered to Allied forces thus ending World War II.