A riot breaks out in Haymarket Square - May 04, 1886 - HISTORY.com

What begins as a peaceful labor protest in Haymarket Square in Chicago, Illinois, turns into a riot, leaving more than 100 wounded and 8 police officers dead. After Chicago authorities arrested and detained nearly every anarchist and socialist in town, eight men, who were either speakers in or organizers of the protest, were charged with murder.

The day before the riot, a couple of people were killed and others were wounded in an unprovoked attack by police officers firing into a crowd of striking workers at the nearby McCormick Reaper Works. Despite tension the following day, the crowd at Haymarket Square was listening quietly to speakers advocating a mandatory eight-hour workday for employees. As the final speaker was winding the rally down, police officers forced their way toward the stage to disperse the crowd, provoking someone to throw a bomb into the crowd.

After the explosion, officers began firing wildly in all directions, inciting a riot among protestors.About sixtypolice officers were wounded and eight died. Although the public was later led to believe that the deaths resulted from the bomb, seven of the eight fatalities and the great majority of the injuries were caused by shots fired by fellow officers during the confusion.

Despite the lack of evidence linking the eight anarchists to the bomb, Chicago authorities clamped down on the radicals with the full support of the public. The defendants were widely believed to be guilty before the trial began. In fact, jury selection at the trial took a full 21 days. Not a single juror was accepted in the first eight days because virtually every one was convinced that the defendants were guilty.

Seven of the eight defendants received death sentences. On November 11, 1887, four of the defendants were hanged. One man, also scheduled for execution, killed himself the day before. Governor John Atgeld pardoned the remaining three defendants in 1893, after they had served seven years in prison.