On Saturday, May 1, thousands of workers who went on strike and attended rallies that were held throughout the United States sang from the anthem, Eight Hour. The chorus of the song reflected the ideology of the Great Upheaval, "Eight Hours for work. Eight hours for rest. Eight hours for what we will." Estimates of the number of striking workers across the U.S. range from 300,000 to half a million.
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When the end-of-the-workday bell sounded, however, a group of workers surged to the gates to confront the strikebreakers. Despite calls for calm ... the police fired on the crowd.
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A New York Times article, with the dateline May 4, and headlined "Rioting and Bloodshed in the Streets of Chicago ... Twelve Policemen Dead or Dying", reported that Fielden spoke for 20 minutes, alleging that his words grew "wilder and more violent as he proceeded". Another New York Times article, headlined "Anarchy's Red Hand" and dated May 6, opens with: "The villainous teachings of the Anarchists bore bloody fruit in Chicago tonight and before daylight at least a dozen stalwart men will have laid down their lives as a tribute to the doctrine of Herr Johann Most." It referred to the strikers as a "mob" and used quotation marks around the term "workingmen"
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A harsh anti-union clampdown followed the Haymarket incident and the Great Upheaval subsided. Employers regained control of their workers and traditional workdays were restored to ten or more hours a day. There was a massive outpouring of community and business support for the police and many thousands of dollars were donated to funds for their medical care and to assist their efforts. The entire labor and immigrant community, particularly Germans and Bohemians, came under suspicion.
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The association of May Day with the Haymarket martyrs has remained strong in Mexico. Mary Harris "Mother" Jones was in Mexico on May 1, 1921, and wrote of the "day of 'fiestas'" that marked "the killing of the workers in Chicago for demanding the eight-hour day". In 1929, The New York Times referred to the May Day parade in Mexico City as "the annual demonstration glorifying the memory of those who were killed in Chicago in 1887". The New York Times described the 1936 demonstration as a commemoration of "the death of the martyrs in Chicago"