In which US city did the 1886 Haymarket affair take place?

In which US city did the 1886 Haymarket affair take place? Chicago.

The Haymarket affair took place at Haymarket Square in Chicago on 4 May 1886. What began as a peaceful labor demonstration supporting an eight-hour workday turned violent when an unidentified person threw a bomb toward police who were moving to disperse the crowd. Gunfire followed, killing and wounding both police officers and civilians.

The rally grew out of intense labor conflict in Chicago, then a major industrial center with a large immigrant workforce. The previous day, police had fired on striking workers at the McCormick Harvesting Machine Company plant, and the Haymarket meeting was organized in response. Speakers included prominent anarchist and labor activists such as August Spies, Albert Parsons, and Samuel Fielden.

Eight anarchists were prosecuted for conspiracy even though the person who threw the bomb was never identified. All were convicted; four were later executed, one died by suicide in prison, and the remaining defendants were eventually pardoned by Illinois Governor John Peter Altgeld in 1893. The affair became a defining symbol of labor rights and helped inspire international May Day observances.