Halloween evolved from the Celtic festival of Samhain, which marked the end of the Celtic calendar year in Ireland, Scotland, and the Isle of Man. They believed it was a time when spirits or fairies could enter our world, and the Celts would set out treats and food to appease the spirits - sometimes, a place at the table was even set for the souls of the dead. Wiccans continue to celebrate Samhain as a New Year's Eve celebration today.