On arrival in the Harz on April 27, we spotted witches on practically each corner of every street in the village where we stayed, Sankt Andreasberg. We soon learned that this had to do with witches and the celebration of 'Walpurgis Night' on April 30. It is the Christian feast day of Saint Walpurga, an 8th-century abbess. She was hailed by the Christians of Germany for battling pest, rabies and whooping cough. She was also known to repel the effects of witchcraft.
According to 17th century German tradition, sorcerers and witches gathered on May Day eve on a Hexennacht or "Witches' Night". The Western Christian Church established the Feast of Saint Walpurga on the same night, believing that Saint Walpurga counteracted the evil magic.
In Germanic folklore, this witches' meeting took place on the Brocken, the highest peak in the Harz mountains. (info from Wikipedia)
Well, we thought it wise to stay as far away from the Brocken as we could on the night of April 30..
..though apparently some witches didn't go either as flying on a broomstick can be quite difficult :)