Halloween originates from the ancient Celtic festival of Samhain, traditionally celebrated in Ireland, Scotland, and parts of Britain. Samhain marked the end of the harvest season and the beginning of winter, a time when the boundary between the living and the dead was believed to be especially thin. People lit bonfires and wore costumes to ward off or disguise themselves from roaming spirits. Over time, Christian practices were layered onto the older beliefs, notably with All Saints’ Day (All Hallows’ Day) being established on November 1. The eve of that feast became All Hallows’ Eve, which eventually contracted to Halloween. In the centuries that followed, these customs blended with local harvest traditions and later with American cultural influences, giving rise to many of the modern Halloween activities such as trick-or-treating, pumpkin carving, and costume parades.