On the night of May 4, 1886, during a peaceful demonstration of labor activists in haymarket square in Chicago, a dynamite bomb was thrown into the ranks of police -trying to disperse the crowd. The officers immediately ...On the night of May 4, 1886, during a peaceful demonstration of labor activists in haymarket square in Chicago, a dynamite bomb was thrown into the ranks of police -trying to disperse the crowd. The officers immediately opened fire, killing a number of protestors and wounding some two hundred others.