Legend has it that on Walpurgisnacht or May Eve, witches fly their broomsticks to meet the devil at the summit of the Brocken Mountain in Harz. In towns and villages scattered throughout the mountain region, locals make bonfires, dress in devil or witch costumes and dance into the new month of May.  

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The devil and his cortege arrive on boats in Stiege, GermanyGetty
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A man in a devil costume arrives at a Walpurgis night pagan festival in the town of Stiege in the Harz mountain region of GermanyReuters
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Two women dressed as witches pose in front of a bonfire in Stiege, GermanyGetty
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People stand by a lake as they watch fireworks explode over a Walpurgisnacht pagan festival in StiegeReuters

A similar festival is held every year in Scotland. The Beltane Fire Festival is celebrated by  Celtic neopagans and Wiccans in Edinburgh to mark the beginning of summer.

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A man wearing antlers holds a torch during the Beltane Fire Festival in EdinburghReuters
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Participants wait for the start of the Beltane Fire Festival in EdinburghReuters
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Participants perform during the Beltane Fire Festival in EdinburghReuters