In German folklore, Walpurgis Night was believed to be the night of a witches' meeting on the Brocken, the highest peak in the Harz Mountains, a range of wooded hills in central Germany.
Best wishes on Walpurgisnacht to all who observe the day. May your will be done and your ends be achieved.
I've shared the Hexenbrut video with a number of people. If you're interested, there's a class on Youtube which teaches you that dance.