This weekend, kids across the country will don spooky costumes and go trick-or-treating. But did you know the origins of those traditions go back to an ancient Celtic festival involving animal sacrifice and a cave of demons?

Rathcroghan was the center of an ancient society in present-day Ireland. You can find the roots of Halloween in its annual New Year’s festival when people would dress up like ghouls to avoid capture by Pagan spirits who were thought to emerge from a cave connected to the underworld.

Now some people in Ireland are hoping for UNESCO World Heritage status for the site, which remains largely unexcavated.

Here & Now‘s Scott Tong speaks with Mike McCarthy, a tour guide at Rathcroghan.

This article was originally published on WBUR.org.

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