Bosses hired thugs who committed mass murder - literally. In 1913, strikebreakers working for the Calumet and Hecla Mining Company started a stampede during a union Christmas party that killed 73 people, including many copper miners' children:

https://en.wikipedia.org/wiki/Italian_Hall_disaster

Workers didn't take this lying down. Violence was met with violence. Bombs went off outside factories and stately mansions. There was gunfire and arson.

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