We celebrate Halloween on the 31st of October because in that night of the year is when the ghosts, the witches, and the fairies creatures are especially active.
Why do we celebrate halloween?
The easy answer to this question is that no one really knows the origins of Halloween.
What we do know for sure is that Halloween is on the eve of a major Catholic festival, All Saints' day (on the 1st November) and the eve of the pagan Celtic festival known as Samhain.
In the past, there were three days between the 31st October and the 2nd November with pagan and Christian celebrations intermingled in a fascinating way which were perfect examples of superstition strugglings with religious belief.
Currently, it is widely thought that Halloween originated as a pagan Celtic festival of the dead related to the Irish and Scottish Samhain, but there is no evidence that it was connected with the dead in pre-Christian times.
The following link is aimed to do a webquest related to Halloween. Enjoy it.
http://www.webquest.es/webquest/halloween-and-jack-olatern
Regards,
BFA SCHOOL OF ENGLISH.