May Day typically May 1
Walpurgisnacht celebrations of pagan origin are traditionally held on the night before May Day, including bonfires and the wrapping of a Maibaum (maypole).
Walpurgis Night (/vælˈpʊərɡɪs, vɑːl-, -ˈpɜːr-/), an abbreviation of Saint Walpurgis Night (from the German Sankt Walpurgisnacht [zaŋkt valˈpʊʁɡɪsˌnaxt]), also known as Saint Walpurga's Eve (alternatively spelled Saint Walburga's Eve), is the eve of the Christian feast day of Saint Walpurga, an 8th-century abbess in Francia, and is celebrated on the night of 30 April and the day of 1 May.[5][6] This feast commemorates the canonization of Saint Walpurga and the movement of her relics to Eichstätt, both of which occurred on 1 May 870.[7]
Saint Walpurga was hailed by the Catholic Christians of Germany for battling "pest, rabies, and whooping cough, as well as against witchcraft". Catholics prayed to God through the intercession of Saint Walpurga in order to protect themselves from witchcraft, as Saint Walpurga was successful in converting the local populace to Christianity. In parts of Europe, people continue to light bonfires on Saint Walpurga's Eve in order to ward off evil spirits and witches.
https://en.wikipedia.org/wiki/May_Day