Feast of Beltane Long ago, Celts celebrated Beltane, which was a calendar feast that welcomed summer. Bonfires figured largely into this celebration, and some activities included dancing around the fire, burning effigies of witches, and hearding cattle in between bonfires. Fire was seen as a purifying source. In recent years, neopagans have begun to celebrate Beltane once more.
May Day is related to the Celtic festival of Beltane and the Germanic festival of Walpurgis Night. – it has traditionally been an occasion for celebration. 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. http://en.wikipedia.org/wiki/May_Day