Tsutomu Yamaguchi, a resident of Nagasaki, was in Hiroshima on business for his employer Mitsubishi Heavy Industries when the city was bombed at 8:15 am, on August 6, 1945. He returned to Nagasaki the following day, and despite his wounds, he returned to work on August 9, the day of the second atomic bombing. That morning he was telling his supervisor how one bomb had destroyed the city, to which his supervisor told him that he was crazy, and at that moment the Nagasaki bomb detonated.
Sources: Wikipedia and this ABC News story.
Funny but not funny!
Poor bastard.