May Day is a public holiday usually celebrated on 1 May or the first Monday
of May. It is an ancient festival of Spring and a current traditional spring
holiday in many European cultures. Dances, singing, and cake are usually
part of the festivities.   

Celebrating the first day of the month of May began as an ancient
Northern Hemisphere spring festival. It is usually a public holiday
and also a traditional holiday in many cultures. The celebration of 
May Day coincides with International Workers’ Day in countries 
with May Day festivities that include dancing and singing. .