After the nuclear holocaust of WW3 on earth in the Star Trek universe, how long after that did it take for everything to be completely rebuilt into the utopian society it eventually became? Because I can imagine a lot of parts of earth would have massive amounts of radiation that would take hundreds of years to completely go away. So do you think by Kirk's time there were still some parts of earth (or the former United States even) that were still inhabitable due to the radiation levels? Or was the Federation able to build some kind of device to make the radiation go away faster? I've always wondered.....