Working-class radicals understood the unique power of collective action, fighting to ensure that the aggression of employers was often met by a groundswell of workers resistance.
Today Is Our Day: This May Day, we should celebrate the historic triumphs of the labor movement and the struggles to come. By Jonah Walters 5-1-16
The first May Day was celebrated in 1886, with a general strike of three hundred thousand workers at thirteen thousand businesses across the United States. It was a tremendous show of force for the American labor movement, which was among the most militant in the world.
Many of the striking workers who numbered forty thousand in Chicago alone rallied under the banners of anarchist and socialist organizations. Trade unionists from a variety of ethnic backgrounds many of them recent immigrants marched shoulder-to-shoulder, making a unified demand for the eight-hour day.
The movement to limit the workday posed a significant threat to American industrialists, who were accustomed to demanding much longer hours from their workers.
In the late nineteenth century, successive waves of immigration brought millions of immigrants to the United States, many of whom sought work in factories. Because unemployment was so high, employers could easily replace any worker who demanded better conditions or sufficient wages so long as that worker acted alone. As individuals, workers were in no position to oppose the dehumanizing work their bosses expected of them ...
Much more here:
https://www.jacobinmag.com/2016/05/may-day-history-iww-haymarket-american-labor-movement/
May Day 1913: