May 1, 2010

International Workers' Day is the commemoration of the Haymarket Massacre in Chicago in 1886, when Chicago police fired on workers during a general strike for the eight hour day, killing several demonstrators and resulting in the deaths of several police officers, largely from friendly fire. In 1889, the first congress of the Second International, meeting in Paris for the centennial of the French Revolution and the Exposition Universelle, following a proposal by Raymond Lavigne, called for international demonstrations on the 1890 anniversary of the Chicago protests. These were so successful that May Day was formally recognized as an annual event at the International's second congress in 1891. The May Day Riots of 1894 and May Day Riots of 1919 occurred subsequently.^{[citation needed]} In 1904, the International Socialist Conference meeting in Amsterdam called on "all Social Democratic Party organizations and trade unions of all countries to demonstrate energetically on May First for the legal establishment of the 8-hour day, for the class demands of the proletariat, and for universal peace." As the most effective way of demonstrating was by striking, the congress made it "mandatory upon the proletarian organizations of all countries to stop work on May 1, wherever it is possible without injury to the workers."