May Day was born May 4, 1886 in the city of Chicago during a general strike against the McCormick Harvesting Machine Company.
The police open fire on the workers at the plant and four were killed.
A mass rally was held at Haymarket Square the next day and 12 workers were killed.
A pro-business trial by Judge Joseph E. Gary lead to the hanging of seven anarchists;August Spies, Albert Parsons, Adolph Fischer, George Engel, Louis Lingg, Michael Schwab, Samuel Fielden and Oscar Neebe.
Thus,birth of May Day as an international labour day to remember the Haymarket martyrs.