May 1 is May Day, one of the oldest festivals in Northern Hemisphere.
This spring festival is a public holiday in number of countries.
May Day is closely connected to another two pagan holidays:
Beltane, the Celtic festival, and
Walpurgis Night, the German festival.
The earliest May Day celebrations date back to the pre-Christian times, when festival of Flora, or Floralia, the Roman goddess of flowers, was observed.
Beltane was most commonly observed on April 30, that was a traditional summer holiday.
Since May was the first month of the summer, this holiday honored the beginning of the season.