Early in 1939, the world's scientific community discovered that German physicists had learned the secrets of splitting a uranium atom. Fears soon spread over the possibility of Nazi scientists utilizing that energy to produce a bomb capable of unspeakable destruction.  

   Scientists Albert Einstein, who fled Nazi persecution, and Enrico Fermi, who escaped Fascist Italy, were now living in the United States. They agreed that the President must be informed of the dangers of atomic technology in the hands of the Axis powers. Fermi traveled to Washington in March to express his concerns on government officials. But few shared his uneasiness.  

   Einstein penned a letter to President Roosevelt urging the development of an atomic research program later that year. Roosevelt saw neither the necessity nor the utility for such a project, but agreed to proceed slowly. In late 1941, the American effort to design and build an atomic bomb received its code name — the Manhattan Project.  

   After this milestone, funds were allocated more freely, and the project advanced at breakneck speed. Nuclear facilities were built at       Oak Ridge, Tennessee      and Hanford, Washington. The main assembly plant was built at Los Alamos, New Mexico. Robert Oppenheimer was put in charge of putting the pieces together at Los Alamos. After the final bill was tallied, nearly $2 billion had been spent on research and development of the atomic bomb. The Manhattan Project employed over 120,000 Americans.