Halloween, is a holiday celebrated on the night of October 31st. Traditional activities include trick-or-treating, costume parties, viewing horror films, visiting "haunted houses", and participating in traditional autumn activities such as hayrides (which may have "haunted" themes).

Halloween originated under the name of Samhain as a Pagan festival among the Celts of Ireland and Great Britain. Irish and Scottish immigrants carried versions of the tradition to North America in the nineteenth century. Other western countries have embraced the holiday as a part of American pop culture in the late twentieth century.

Halloween is now celebrated in parts of the western world, most commonly in Ireland, the United States, Canada, Puerto Rico, the United Kingdom and sometimes in Australia and New Zealand. In recent years, the holiday has also been celebrated in parts of Western Europe.