The celebration of Halloween has a tradition that includes dressing up in costumes. It may also include visits to haunted houses and trick-or-treating. So how did it all begin? It started 2,000 years ago in Ireland and Scotland. The Celts as they were known, celebrated fall. On the last day of October, they also celebrated the deceased. The Celts also believed in evil spirits. To chase away the spirits they would dress up in costumes and make noise in the street. The traditional colors of Halloween are no surprise. Orange for fall and black representing death.