If this is a dumb question then I apologise. I couldn't think of anywhere else to ask it. Doing some reading on the nuclear bomb tests during WWII, I found it odd that the actual development of the bombs only took just over two years from when the team was brought together to when the bombs were dropped, and yet they only had theories to work with back then and on top of that, were working with 1940's technologies. Yet the knowledge of making the bombs is now well known and yet countries like Iran have been "developing" them for... how many years now? So where are all the nuclear weapons? If a team of scientists working from theories could do it in two years in the 1940's, why can't teams of scientists in Iran do it over the last thirty odd years?