Police demanded a fair price for labor and eight hours of labor time, police on this day in 1886 caused a series of fire brigades on activists of the market in Chicago's O market. O market was rolled in blood. The blood donation of the workers was not futile. Workers' movement was much stronger. Finally, the authorities were forced to accept the demand for labor for eight hours. In 1889, it was decided to celebrate the day of the Second International Labor Conference in Paris on May Day. Since then, the wet day of blood is being celebrated as May Day.
From @mahbub6213