During the 1930's workers and unionists invented the sit-down strike--a powerful and revolutionary weapon to bring industrial employers to the bargaining table. It demanded of employees that they stay at their workplaces, but without working. The movement proved effective, but it was controversial, not just among management but also among some labor leaders. This photo shows the first successful sit-down strike, staged in 1937 by the United Auto Workers at a GM factory in Flint, Michigan. GM capitulated (gave in), handing the labor movement one of its most important victories.