in medieval and modern Europe, holiday (May 1) for the celebration of the return of spring. The observance probably originated in ancient agricultural rituals, and the Greeks and Romans held such festivals. Although later practices varied widely, the celebrations came to include the gathering of wildflowers and green branches, the weaving of floral garlands, the crowning of a May king and queen, and the setting up of a decorated May tree, or Maypole, around which people danced. Such rites originally may have been intended to ensure fertility for crops and, by extension, for livestock and humans, but in most cases this significance was gradually lost, so that the practices survived largely as popular festivities. Among the many superstitions associated with May Day was the belief that washing the face with dew on the morning of May 1 would beautify the skin. Because the Puritans of New England considered the celebrations of May Day to be licentious and pagan, they forbade its observance, and the holiday never became an important part of American culture.

In 1889 the International Socialist Congress designated May 1 as a day in support of workers, and in some countries May Day subsequently came to be marked by parades and ceremonies noting especially the contributions of labour unions. After World War II, in the Soviet Union (Union of Soviet Socialist Republics) and the Soviet-bloc countries of eastern Europe, May Day parades became important political and military observances. The annual Soviet parade in Red Square in Moscow, presided over by top government and Communist Party functionaries, was known for its display of the country's military might. With the breakup of the Soviet Union and the fall of communist governments in eastern Europe, such celebrations declined in importance. In some countries, however, May Day has continued to be observed as a workers' holiday, similar to Labor Day in the United States.