#OTD in 1945, the U.S. dropped a second atomic bomb on Japan, striking the city of Nagasaki. Coupled with the attack on Hiroshima three days previously, the attack persuaded Japan to announce on Aug. 14 that it would surrender. Formal surrender occurred on Sept. 2, 1945, thus ending, after six years and one day, the deadliest war in history. 70 million soldiers, sailors, and airmen took part, more than 1 in 4 were killed, and including civilians, total deaths topped 50 million.