Halloween is a celebration observed in a number of countries on 31 October, the eve of the Western Christian feast of All Hallows’ Day. It begins the three-day observance of Allhallowtide, the time in the liturgical year dedicated to remembering the dead, including saints (hallows), martyrs, and all the faithful departed.
It is widely believed that many Halloween traditions originated in the British Isles from Celtic harvest festivals which may have pagan roots, particularly the Gaelic festival Samhain, and that this festival was Christianized as Halloween.
Halloween activities include trick-or-treating, attending Halloween costume parties, decorating, carving pumpkins into jack-o’-lanterns, lighting bonfires, apple bobbing and divination games, playing pranks, visiting haunted attractions, telling scary stories and watching horror films. In many parts of the world, the Christian religious observances of All Hallows’ Eve, including attending church services and lighting candles on the graves of the dead, remain popular.