MAY DAY. 1ST MAY 2016 This is an annual celebration of the International labour movement and is also called International Worker’s Day. May Day is a holiday in eighty countries and celebrated by the socialist movement supporting the rights of workers. The day commemorates 1st May 1886 when a peaceful rally of workers at Haymarket Square in Chicago, USA was demanding an eight hour working day. The rally was bombed and faced the action of the police.