May Day, the International Workers' Day, is celebrated on May 1, to commemorate the working class struggle for an eight-hour workday, immortalised by the conflicts from the 1886 Haymarket affair in Chicago. It was established by an international federation in 1889, now recognised globally to promote worker solidarity and rights. On May 1, Chicago witnessed a great outpouring of workers, who laid down tools at the call of the organised labour movement of the city.