The Manhattan Project had its origins in 1939, when U.S. scientists urged President Franklin D. Roosevelt to establish a program to study the potential military use of fission; $6,000 was appropriated for the task. By 1942 the project was code-named Manhattan, for the site of Columbia University, where much of the early research was done. The first nuclear reactor was constructed by Enrico Fermi at the University of Chicago in 1942. In 1943 a laboratory to construct the bomb was established at Los Alamos, New Mexico, with a staff of scientists headed by J. Robert Oppenheimer. Manhattan Project scientists detonated the first atomic bomb in a test near Alamogordo in southern New Mexico. By the time the Manhattan Project ended, it had cost some $2 billion and involved 125,000 people.