Halloween originated from the ancient Celtic festival of Samhain, marking the end of summer and the harvest season and the beginning of the dark cold winter. The Celts believed that on Samhain, the boundary between the worlds of the living and the dead became blurred and the spirits of the dead returned to Earth. They would build bonfires and wear costumes to ward off these spirits. Over time, Halloween evolved with Christian influences to become a day of remembrance for saints and martyrs. Traditions spread from Celtic lands to England and incorporated activities like nut cracking, apple bobbing and mischievous pranks.