Where did Halloween come from? | Harvard Explains

Have you ever wondered where trick-or-treating came from? Or why we carve spooky faces into pumpkins? The origins of both practices, and Halloween itself, come from the Celtic festival of Samhain. Ciara Ní Riain, lecturer at Harvard University's Department of Celtic Languages & Literatures, tells the story of how the ancient Irish festival morphed into what we now know as Halloween.