In Europe, the day (May 1) for traditional springtime celebrations.
It probably originated in pre-Christian agricultural rituals. Celebrations included a May king and queen, a Maypole, and people carrying trees, green branches, or garlands. May Day was designated an international labour day by the International Socialist Congress of 1899, and it remains the standard Labour Day worldwide, with a few exceptions, including Canada and the U.S. A major holiday in the Soviet Union and other communist countries, it was the occasion for important political demonstrations.