Halloween or All Hallows Evening is a celebration that has its roots to pagan beliefs although etymologically the term has Christian coinage. Halloween celebrations originated from the pagan custom of paying homage to the dead and also to Harvest.
However, in modern times, Thanksgiving is more related to Harvest Festival, while Halloween is meant for honoring the Saints and the departed souls. It is celebrated on October 31st every year. Trick-o-Treat is an integral part of modern Halloween festivities where people visit friends and neighbors dressed in costumes asking for treats.
Carving Jack-o-Lanterns, lighting bonfire, decorating places and even presenting food horror-themed are other ways that keep up the celebrations on this holiday.