Hallowe'en has a long history: over 2000 years ago, the pre-Christian Celtic festival of Samhain was held on 31st October. This was considered to be the last night of Autumn before the onset of Winter. It celebrated the end of the harvest and the beginning of the Celtic new year on 1st November, which made 31st October the Celtic New Year's Eve. The Druids or Celtic high priests believed that the supernatural world drew closer to the physical world on this night: a time when living beings were more susceptible to the power and influence of magic.
The word Hallow is old English for saint. All Hallows' Eve is the night before All Hallows or All Saints, which falls on 1st November ~ All Hallows eventually became known as Hallowe'en.
However you may choose to celebrate this day, remember that there are unseen influences in our lives ~ maybe we just need to believe...