This is a unique behind the scenes look inside a World War 2 American defense plant producing the complex M3 Lee medium tank. The Lee was the Army's first mass produced World War 2 battle tank, as seen in the Humphrey Bogart Hollywood classic "Sahara." It featured a turret mounted 37mm quick firing antitank gun and a hull mounted 75mm gun. It was exported in large numbers to Britain, Commonwealth countries and the Soviet Union as the "Grant," with several British mandated modifications. It first saw combat in North Africa in 1942 where it was more than a match for contemporary Axis tanks like the Panzer III and proved very reliable in desert conditions with its air cooled aircraft engine. When large numbers of M4 Shermans became available in 1943 and the Germans introduced their powerful Panther & Tiger tanks, the M3 was withdrawn from Europe, but continued in service a little longer in the Pacific & with the Indian Army. Inside the newly constructed Detroit Tank Arsenal, you'll see all aspects of M3 assembly line production using 10,000 workers. One of the under appreciated aspects of the process was the design and production of over 4,000 precision machine tools needed to manufacture and assemble all elements of the Lee, all of which had to be in place with trained workers before a single tank could roll off the assembly line. The ability of American industry to convert seemingly overnight from peace time production of automobiles and other consumer goods to mass producing weapons of war for U.S and Allied Armed Forces was a key to winning the conflict.