In 1938 was discovered by nuclear physicists in a laboratory in Berlin, Germany, the first atomic bomb possible, after Otto Hahn, Lise Meitner and Fritz Strassman discovered nuclear fission. When an atom of radioactive material splits into lighter atoms, there's a sudden, powerful release of energy. This came by years after Einstein Relativity Theory and Curie's knowledge that energy was originating from the subatomic level.