May 1 is International Labor Day and a national holiday of Cambodia. KHANA closes its office on this day. International Workers' Day is a celebration of the international labor movement. It commonly sees organized street demonstrations and marches by working people and their labor unions throughout most of the world. May 1 is a national holiday in more than 80 countries including Cambodia.
International Labor Day is the commemoration of the 1886 Haymarket Massacre in Chicago, when Chicago police fired on workers during a general strike for the eight hour workday, killing several demonstrators and resulting in the deaths of several police officers, largely from friendly fire. In 1889, the first congress of the Second International, meeting in Paris for the centennial of the French Revolution and the Exposition Universelle, following a proposal by Raymond Lavigne, called for international demonstrations on the 1890 anniversary of the Chicago protests. May Day was formally recognized as an annual event at the International's second congress in 1891.