In 1884, in America, the Federation of Organised Trades and Labor Unions passed a resolution in their meeting that all legal ways for their demand to reduce the working hours from 16 to 8 had failed. Therefore they decided to go on strike. The movement gained momentum and on 1st May 1886, a strike call was given. The center of this movement was Chicago. To foil the strike additional police were hired, money for which was given by the Industrialists, For two days the strike remained peaceful.

On 3rd May, near the McCormick Harvesting Machine Co. factory, police resorted to unprovoked firing upon unarmed and peaceful demonstration. Resultantly, four laborers died and several other were injured. The next day on May 4th, the organizers announced a big rally against the criminal action of police at market square. The gathering was peaceful. When the last leader was delivering his speech,the police started firing on laborers. Several laborers died and hundreds were injured. Police made an excuse that someone from the gathering hurled a grenade, which resulted in death of one police man.

A fake case was registered against labor leaders and 8 leaders were awarded the death sentence. Albert Parson, August Spize, Adolf Fischer and George Angel were hanged on November 11, 1887. Louise Ling committed suicide in jail. The rest of the three were pardoned in 1893. In 1889 it was decided to declare May 1 as labor day. On the first of May 1890, the first May Day was observed in the memory of innocent martyred of Labor Movement. Gradually, the day became a most important phenomena in Labor Movements around the world and being observed now by the Governments every year.

The earliest May Day celebrations appeared in pre-Christian times, with the festival of Flora, the Roman Goddess of flowers, and the Walpurgis Night celebrations of the Germanic countries. It is also associated with the Gaelic Beltane. Many pagan celebrations were abandoned or Christianized during the process of conversion in Europe. A more secular version of May Day continues to be observed in Europe and America. In this form, May Day may be best known for its tradition of dancing the Maypole and crowning of the Queen of the May. Various Neopagan groups celebrate reconstructed (to varying degrees) versions of these customs on May the 1st.

The day was a traditional summer holiday in many pre-Christian European pagan cultures. While February 1 was the first day of Spring, May 1 was the first day of summer; hence, the summer solstice on June 25 (now June 21) was Midsummer. In the Roman Catholic tradition, May is observed as Mary's month, and in these circles May Day is usually a celebration of the Blessed Virgin Mary. In this connection, in works of art, school skits, and so forth, Mary's head will often be adorned with flowers in a May crowning. Fading in popularity since the late 20th century is the giving of "May baskets," small baskets of sweets and/or flowers, usually left anonymously on neighbours' doorsteps.

May Day is related to the Celtic festival of Beltane and the Germanic festival of Walpurgis Night. May Day falls exactly half of a year from November 1, another cross-quarter day which is also associated with various northern European pagan and neopagan festivals such as Samhain. May Day marks the end of the uncomfortable winter half of the year in the Northern hemisphere, and it has traditionally been an occasion for popular and often raucous celebrations.

As Europe became Christianized the pagan holidays lost their religious character and either changed into popular secular celebrations, as with May Day, or were merged with or replaced by new Christian holidays as with Christmas, Easter, and All Saint's Day. In the twentieth century, many neopagans began reconstructing the old traditions and celebrating May Day as a pagan religious festival again.