The Haymarket affair (also known as the Haymarket massacre or Haymarket riot) was a demonstration and unrest that took place on Tuesday May 4, 1886, at the Haymarket Square<3> in Chicago. It began as a rally in support of striking workers. An unknown person threw a dynamite bomb at police as they dispersed the public meeting. The bomb blast and ensuing gunfire resulted in the deaths of eight police officers, mostly from friendly fire, and an unknown number of civilians.<4><5> In the internationally publicized legal proceedings that followed, eight anarchists were tried for murder. Four men were convicted and executed, and one committed suicide in prison, although the prosecution conceded none of the defendants had thrown the bomb.
The Haymarket affair is generally considered significant for the origin of international May Day observances for workers.<6><7> In popular literature, this event inspired the caricature of "a bomb-throwing anarchist." The causes of the incident are still controversial. The deeply polarized attitudes separating business and working class people in late 19th-century Chicago are generally acknowledged as having precipitated the tragedy and its aftermath. The site of the incident was designated a Chicago Landmark on March 25, 1992.<8> The Haymarket Martyrs' Monument in nearby Forest Park was listed on the National Register of Historic Places and designated a National Historic Landmark on February 18, 1997.<2>
http://en.wikipedia.org/wiki/Haymarket_affairOrganizers called an outdoor meeting in Haymarket Square--near the city's meatpacking district--to protest the police attacks. The 3,000-person event was smaller than organizers expected. Mayor Carter Harrison even went to the rally to see if there was reason to expect there would be any violence, and seeing that there wasn't, he told the police as much.
With rain setting in, the crowd had thinned out to about a third of its original size. Samuel Fielden was speaking when the police began to attack the crowd on the order of Chief Inspector John Bonfield. At this point, a bomb was thrown--by whom is still unknown. One police officer was killed on the spot, and seven more died of their wounds later. The number of workers killed by the explosion and by the police rampage in the aftermath was less carefully reported upon, though the number of wounded were counted in the hundreds.
In the aftermath, Chicago police used the incident as an excuse to target and round up labor militants and radicals, as the corporate newspapers cheered on the prosecution of "bomb makers" and "red ruffians."