Halloween is celebrated every October 31st and has roots in the Celtic festival, Samhain (old Irish meaning "summer's end").  The ancient Celts believed that the border between this world and the after world became thin on Samhain, allowing spirits (both harmless and harmful) to pass through. The family's ancestors were honored and invited home whilst harmful spirits were warded off. It is believed that the need to ward off harmful spirits led to the wearing of costumes and masks. Their...