Who: Albert Einstien sent a letter to President Franklin D. Roosevelt convincing him to make an atomic bomb. The government started funding research for Enrico Fermi and Leo Szilard. When the Manhattan Project officially began U.S. Army Colonel Leslie R. Groves was appointed to lead the project. Robert Oppenheimer was named director of Los Alamos laboratory. President Truman was the one to call the bombings.
What: The Manhattan Project was a top-secret research and development project to create the atomic bomb. The scientists were researching nuclear fission and nuclear reactions. Then the bombs were dropped.
When: In August 1939, Albert Einstien wrote a letter to President Roosevelt who then formed an advisory committee on uranium. World War II started in Europe, September 1939. The advisory committee on uranium changed its name to the National Defense Research Committee (NDRC) in 1940. 1941 the NDRC formally became the Office of Scientific Research and Development (ORSD). 1942 the ORSD formed the Manhattan Engineering District which formally became the Manhattan project in December 1942. In May 1945 the war ends in Europe. In August 1945 America drops two nuclear bombs on Hiroshima and Nagasaki, Japan, effectively ending WWII.
Where: The main production base was Oak Ridge, Tennessee, where the National Laboratory is still located. The plutonium used to make Fat Man, the nuclear bomb dropped on Nagasaki, Japan, was made in Hanford, Washington, which is where the radioactive nuclear waste remains. Majority of the research was done in Los Alamos, New Mexico, under the supervision of Robert Oppenheimer. This is also where the first nuclear bomb was tested, in what is known as the Trinity Test.
Why: They made the bombs because they believed that the Nazis were researching nuclear reactions and how to use that research for weaponry.
"Had I known that the Germans would not succeed in developing an atomic bomb, I would have done nothing for the bomb."
~ Albert Einstien