On May 4, 1886, one of the most famous pieces of Chicago history played out downtown at Desplaines and Randolph streets.To protest police brutality, radicals held a mass meeting in Haymarket Square. The meeting remained peaceful until police attempted to disperse it, whereupon a bomb was thrown by an individual never positively identified. Seven policemen were killed and 60 others were injured before the violence ended. Amid the panic that followed the resulting riot, August Spies and seven other alleged anarchist labour leaders were convicted of murder on the grounds that they had conspired with or aided an unknown assailant. Many of the eight arrested, however, were not even present at the May 4 event, and their alleged involvement was never proved. Nevertheless, Spies and three other defendants were hanged on November 11, 1887, while another committed suicide. The surviving three were pardoned in 1893 by Illinois Governor John Peter Altgeld—an action widely condemned by industrialists but applauded by labour reformers.
The library has assembled a display of books, photos, and articles to commemorate that day.