Labour Day, aka International Workers' Day, aka May Day is a public holiday that is observed on May 1st in virtually every country in the world except the U.S. Their holidays commemorate the Haymarket Affair, a labor demonstration in Chicago on May 4th, 1886 that turned bloody when a dynamite bomb killed and wounded dozens.
Eight years later, May 11th, 1894, 150,000 members of the American Railway Union went on strike. President Grover Cleveland sent in federal troops - rioting and arson broke out - and it turned into one of the bloodiest episodes in American labor history.
Obviously something needed to happen to defuse these May Day labor eruptions. So, the very next month President Cleveland signed a law declaring Labor Day to be a national holiday in celebration of the American working man and woman.
But definitely not in solidarity with those foreign socialists and rabble rousers on May 1st. No, this holiday will be on the first Monday in September.
