History of Halloween
What is now called Halloween is celebrated on 31st October each year, the day before All Saints or All Hallows Day. The word Halloween has evolved from the words All Hallows Eve, then Hallow Eve.
The Halloween festival was originally an Irish celebration of the harvest, a Celtic pagan harvest festival. The day was celebrated in several North American pagan festivals centred on October 31 each year, and was later given a Christian angle by some missionaries. Some of the older Halloween practices were taken to what is now the USA by 19th century settlers from Ireland and other European nations.
Halloween continued to be celebrated commonly in Ireland, though elsewhere in Europe such celebrations declined. However, in some parts of Europe Halloween has been reimported in the common US form of celebration, with trick and treating, Jack O'Lanterns and so on.
Halloween is most widely celebrated, though, in the USA and Ireland. In the USA it is now a major commercial event, that kick starts the retail festival that runs all the way until Christmas and New Year