Ninety percent of Hiroshima was destroyed as was large amounts of Nagasaki. There wouldn’t have been much useable land left even if there hadn’t been radiation left behind. There wouldn’t have been people around to use it anyway as 275,000 people died directly as a result of the two bombs over a period of five years after they were dropped. One bomb should have been enough to get a surrender from the Japaneses military if used. It is not surprising that they surrendered after both were used.
The discovery of fission had a tremendous effect on the world, starting to bring the world into the atomic age. It caused the research of nuclear weapons. It then lead to the first atomic bomb called the Gadget. That then lead to the Fat Man and Little boy atom bombs. Finally it caused the bombing of the two cities of Hiroshima and Nagasaki. While the morality of the scientists and leaders of the time and their actions could be called into question, they certainly brought the world into the atomic