To imagine what would spur a riot of tens of thousands of people over a shuttered auto factory, you need a little context. In 1936, with the Depression waning but not over, workers at GM's factories in Flint, Mich., earned about $20 a week, roughly half what they had made before the crash. They had no rights; they could be fired at will, or for injuries sustained while working. When the fledgling United Auto Workers organized sit-down strikes in other cities, the Flint Fisher Body plant workers shut down on Dec. 30. On this date in 1937, after turning off the heat to the plant, GM security and Flint police took away the ladder that had brought the strikers food; when the workers broke open a door to get supplies from supporters outside, a riot ensued. Police shot tear gas into the plant and used live ammunition; strikers threw bolts and parts at the police. By nightfall, Michigan's governor had ordered the National Guard to Flint, but allowed the strike to continue. GM agreed to its first UAW contract on Feb. 11, granting a 5 percent raise and banning unpaid overtime.