Well that's what I'm confused about. The bomb that was dropped on Hiroshima was a Uranium 235, the one on Nagasaki was Plutonium 39 both with a half life of 700, million years and 24,000 years respectively. Yet today both cities are thriving. I believe when the bombs dropped both cities were radioactive for several weeks but not uninhabited because people just didn't understand the long term effects of radiation. Both bombs detonated in the air, I believe which could be a reason why both cities are now habitable with near negligible radiation. I guess in this tl, little boy and fat man would detonate much in the same way in Berlin and possibly another German city, unless these bombs actually detonated right on the ground which would be more devastating.How long were Hiroshima and Nagasaki uninhabitable for?