FILE - In this Aug. 9, 1945, file photo, a giant column of smoke rises more than 60,000 feet into the air, after the second atomic bomb ever used in warfare explodes over the Japanese port town of Nagasaki, dropped by the U.S. Army Air Forces B-29 plane "Bockscar." The U.S. dropped a uranium bomb on Hiroshima on Aug. 6, 1945, killing 140,000 people in the world's first atomic attack. Three days later, it dropped a plutonium bomb on Nagasaki, killing another 74,000. (AP Photo, File)