walpurisnacht

Our faithful chronicler reminds that on this night, the date shared with many other momentous occasions including the annexation of Hawaii (1900), the fall of Saigon (1975) and the coming out of the tv character of actor and comedian Ellen DeGeneres (1997), Beltane Eve is observed (previously here and here) in the northern hemisphere, coopted locally as the syncretion of the day before the feast day of Saint Walpurga, an abbess and Anglo-Saxon missionary from Devonshire to the Frankish Empire.
Converts were encouraged to pray to her for intercession and protection from witchcraft—though Walpurga’s patronage was restricted to hydrophobia, odd given the witch connection, and sailors in distress. Though there’s a lot of regional variation in the way the holiday is kept across northern Europe, common customs include bonfires—a ceremonial burning and/or celebration of the diabolical and a sort of sealing off the portal, marking the last opportunity that the supernatural can cross over from the nether world, until Halloween.