Celts believed that on the night before the new year, the boundary between the worlds of the living and the dead became blurred. On the night of October 31, they celebrated Samhain, when it was believed that the ghosts of the dead returned to earth.
Halloween is celebrated annually on October 31. Just think about a bunch of frightening fantasies and the scary stories featuring ghosts, witches, monsters, and all things that go bump in the night then your thinking about one of the finest holidays of the year.
The disembodied spirits of all those who had died throughout the preceding year would come back in search of living bodies to possess for the next year. It was believed to be their only hope for the afterlife.
The Celts believed all laws of space and time were suspended during this time, allowing the spirit world to intermingle with the living.