The origin of nuclear weapons began in Europe (a group of scientists discovered nuclear fission). The inventor was Robert Oppenheimer, but his director developed nuclear weapons on the premise that Lis Maitenaz and Oddo Hahn discovered nuclear fission. If they were the first people to develop nuclear weapons, they would not be Oppenheimer, but a group of German scientists.

At the beginning of 1939, German chemist O. Hahn and physical chemist F. Strassman published papers on nuclear fission of uranium atoms. Within a few weeks, scientists from many countries verified this discovery and further suggested that it was possible to create conditions for this fission reaction to proceed on its own, thus opening up a broad prospect of using this new energy to create wealth for mankind.

In the United States, the Hungarian physicist Zilad Leo, who moved from Europe, first considered that once fascist Germany mastered the atomic bomb technology, it might bring serious consequences. After he and several other scientists who immigrated to the United States from Europe rushed to promote it,1In August, 939, physicist A. Einstein wrote to the 32nd President of the United States, F. D. Roosevelt, suggesting the development of an atomic bomb, which attracted the attention of the American government.