(Bonus) German Nuclear Weapons Program during WWII - Wikipedia

Then and Now: Global History and Culture

(Bonus) The Uranverein (English: "Uranium Club") or Uranprojekt (English: "Uranium Project") was the name given to the project in Germany to research nuclear technology, including nuclear weapons and nuclear reactors, during World War II. It went through several phases of work, but in the words of historian Mark Walker, it was ultimately "frozen at the laboratory level" with the "modest goal" to "build a nuclear reactor which could sustain a nuclear fission chain reaction for a significant amount of time and to achieve the complete separation of at least tiny amount of the uranium isotopes." The scholarly consensus is that it failed to achieve these goals, and that despite fears at the time, the Germans had never been close to producing nuclear weapons.