cohesion they needed a centralized, secret research laboratory in a remote location. Scouting for a site in late 1942, Oppenheimer was drawn to New Mexico, not far from his ranch. On November 16, 1942, Oppenheimer, Groves and others toured a prospective site. Oppenheimer feared that the high cliffs surrounding the site would make his people feel claustrophobic, while the engineers were concerned with the possibility of flooding. He then suggested and championed a site that he knew well: a flat mesa near Santa Fe, New Mexico, which was the site of a private boys' school, the Los Alamos Ranch School. The engineers were concerned about the poor access road and the water supply but otherwise felt that it was ideal. The Los Alamos Laboratory was built on the site of the school, taking over some of its buildings, while many new buildings were erected in great haste. At the laboratory, Oppenheimer assembled a group of the top physicists of the time, which he called the "luminaries". Los Alamos was initially supposed to be a military laboratory, and Oppenheimer and other researchers were to be commissioned into the Army. He went so far as to order himself a lieutenant colonel's uniform and take the Army physical test, which he failed. Army doctors considered him underweight at , diagnosed his chronic cough as tuberculosis, and were concerned about his chronic lumbosacral joint pain. The plan to commission scientists fell through when Rabi and Robert Bacher balked at the idea. Conant, Groves, and Oppenheimer devised a compromise whereby the laboratory was operated by the University of California under contract to the War Department. It soon turned out that Oppenheimer had hugely underestimated the magnitude of the project; Los Alamos grew from a few hundred people in 1943 to over 6,000 in 1945. Oppenheimer at first had difficulty with the organizational division of large groups, but rapidly learned the art of large-scale administration after he took up permanent residence on the mesa. He was noted for his mastery of all scientific aspects of the project and for his efforts to control the inevitable cultural conflicts between scientists and the military. He was an iconic figure to his fellow scientists, as much a symbol of what they were working toward as a scientific director. Victor Weisskopf put it thus: At this point in the war, there was considerable anxiety among the scientists that the Germans