White Shirt Day honors the men and women who participated in a sitdown strike at General Motors in 1937. These autoworkers helped the United Auto Workers (UAW) union to become the sole bargaining agent for General Motors autoworkers. The strike ended on this day in 1937.
According to the UAW's website, the traditions of White Shirt Day are simple:
Everyone must wear a white shirt or blouse
Your white shirt must not get dirtier than your boss's shirt
Safety and work rules must be followed.