April 30: Saint Walpurga’s Eve...

"Saint Walpurga was an Anglo-Saxon missionary who was canonized in 870. In addition to fighting against rabies, whooping cough, and pests, Walpurga was held up as a bastion of faith against witchcraft.

That’s where April 30 gets weird. In Germany, April 30 is also Hexxenacht, or the night when witches are said to have celebrations on the Brocken, a tall mountain.

There are folk tales across Europe that equate the day to Halloween, suggesting that the walls between the living and the dead are thin. This practice is immortalized in scenes from Johann Wolfgang von Goethe’s classic play Faust.

It’s still a tradition across the continent to light bonfires on April 30, partially in tribute to the eve of the saint’s day, and partially out of superstition to ward off evil spirits."

https://www.saturdayeveningpost.com/2019/04/the-strange-significance-of-april-30/