Halloween today is all about pumpkins carved with both scary and funny faces, costumed kids, candy, and spooky attractions like haunted houses, but Halloween can trace its roots back to the Celtic festival of Samhain, which was celebrated on November 1. The Celts believed that on this day, the souls of the dead returned home, so people dressed in costumes to confuse them and lit fires to drive away the evil spirits.
In the 8th century, Pope Gregory III moved All Saints Day to November 1, turning a secular event into a religious observance, and...