In modern times, Samhain (a Gaelic word pronounced “SAH-win”) is usually celebrated from October 31 to November 1 to welcome in the harvest and usher in “the dark half of the year.” Celebrants believe that the barriers between the physical world and the spirit world break down during Samhain, allowing more interaction between humans and denizens of the Otherworld. Samhain is a pagan religious festival originating from an ancient Celtic spiritual tradition.