Halloween has its roots in the ancient Celtic festival of Samhain, celebrated over 2,000 years ago in what is now Ireland, the UK, and northern France. Samhain marked the end of the harvest season and the beginning of winter, a time believed to blur the line between the living and the dead. People lit bonfires and wore costumes to ward off roaming spirits. The holiday evolved over centuries, merging with Christian traditions, particularly All Hallows' Eve, the night before All Saints' Day. Today, Halloween is a vibrant celebration marked by costumes, trick-or-treating, and festive gatherings, reflecting its rich history and cultural adaptations.