Halloween originated from the ancient Celtic festival of Samhain, celebrated on November 1st in Ireland, England, and Northern France to mark the end of the harvest season and the beginning of winter. On the night of October 31st, the Celts believed spirits of the dead returned to earth and people wore costumes to avoid being recognized by ghosts. As Christianity spread, the holiday was changed to All Saints' Day on November 1st. The traditions of dressing in costumes and going door-to-door for food or money evolved into modern-day trick-or-treating. Irish immigrants brought Halloween traditions to America in the 19th century, carving jack-o-lanterns from pumpkins instead of turnips