The Haymarket Riot on May 4, 1886 in Chicago is generally considered to have been an important influence on the origin of international May Day observances for workers. In popular literature this event inspired the caricature of "a bomb-throwing anarchist." The causes of the incident are still controversial, although deeply polarized attitudes separating the business class and the working class in late 19th century Chicago are generally acknowledged as having precipitated the tragedy and its aftermath. (read more...)