Historical photo from Los Alamos National Laboratory (LANL). On April 20, 1943, the University of California signed a contract with the United States Army Corps of Engineers to operate a secret laboratory in the mountains of northern New Mexico. The university accepted the task of managing Los Alamos as a service to the nation. The Los Alamos Laboratory sprang up overnight. Throughout the summer of 1943, hundreds of bewildered families moved to Los Alamos to begin an unforgettable adventure. Scientific personnel had only a very general idea about the nature of the work that awaited them. They were instructed to tell their families nothing. Most administrative and technical personnel knew only that they were moving to an unknown place for an unknown length of time. Most lived in trailers and huts put up by the Army in a very short time to try to deal with the massive influx of personnel. Because it was secret, Los Alamos was referred to as "Site Y" or "the Hill". Birth certificates of babies born in Los Alamos during the war listed their place of birth as PO Box 1663 in Santa Fe.