Atomic burst over Nagasaki coloured image On th August during World War II a US bomber dropped the Fat Man atomic bomb over Nagasaki Japan The atomic explosion equivalent to tons of TNT generated a dense column of smoke and a mushroom cloud that rose over kilometres into the air This was the second atomic bomb used in warfare following the atomic bomb over Hiroshima three days earlier Over people died in both cities and thousands were injured Japan surrendered a few days later For the original version of this image see T