Halloween
Halloween, is also known as Hallowe'en, a contraction of "All Hallows' Evening", or All Hallows' Eve, or All Hallows' Even ('evening'). It is a yearly celebration observed in a number of countries on October 31st, the eve of the Western Christian feast of All Hallows (or All Saints).
According to many scholars, it was originally influenced by western European harvest festivals and festivals of the dead with possible pagan roots, particularly the Celtic Samhain. Others maintain that it originated independently of Samhain and has Christian roots.
Typical festive Halloween activities include trick-or-treating (also known as "guising"), attending costume parties, carving pumpkins into jack-o'-lanterns, lighting bonfires, apple bobbing, visiting haunted attractions, playing pranks, telling scary stories, and watching horror films.
In Ireland customs include lighting bonfires, and having firework displays. Halloween is also popular in South America, Australia, New Zealand, Most of continental Europe, Japan, and other parts of East Asia.
All Hallows Eve precedes All Saints' Day on November 1st, also known as All Hallows, Hallowmas or Hallowtide. All Saint's day in turn precedes All Souls' Day on November 2nd. The two days together are known as The Day of The Dead, a major observance in Latin America.
Halloween is proceeded by Mischeif Night, an informal holiday on which children and teens engage in pranks and minor vandalism. Some refer to the night as Pumpkin Night or Mischeif Night
Mischeif Night is known as Devils Night in Detroit, Michigan but escalated to major vandalism and arson.
The escalation prompted the creation of Angel's Night in which up to 40,000 Detroiters volunteer to patrol keep the city safe on these nights. Angels Night has been very successful in reducing crime of all kinds.
Samhain
Samhain is a Gaelic festival marking the end of the harvest season and the beginning of winter or the "darker half" of the year. Most commonly it is held on October 31st and/or November 1st and November 2nd in the Northern Hemisphere. April 30th and/or May 1st and May 2nd in the Southern Hemisphere. Which is halfway between the autumn equinox and the winter solstice for both hemispheres. Along with Imbolc, Beltane and Lughnasadh it makes up the four Gaelic seasonal festivals. It is observed in Ireland, Scotland and the Isle of Man.
In other Celtic areas, related festivals are observed, like the Brythonic Calan Gaeaf (Wales), Kalan Gwav (Cornwall) and Kalan Goañv (Brittany). Samhain is also celebrated my modern Neo-Pagans and it is New year for Wiccans.