How did Halloween start?

Halloween- or Hallows' Eve- can be traced back to Celtic Culture in Ireland. According to their religion, November 1st was New Years' on their calendar. The celebration would start October 1st. The spirits of all who died would rise up and roam the earth on this night. They placed pumpkins to ward off the evil spirits.

People would wear costumes and go "mumming", they would go from door to door giving prayers for treats.