In parts of Northern and Eastern Europe, from Sweden to the Czech Republic, the Mass of Saint Walburga or Walpurgis Night is celebrated on the evening of April 30th.
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. (Wikipedia)