A History of Halloween

Due to Halloween coming up soon, I think it would be a good idea to post here about our favourite archaic or local forms of All Hallow's Eve, or related holidays. (If I misunderstood the purpose of this forum location, I would appreciate the mistake being duly corrected and the thread moved to wherever it should be.)
My personal favourite would probably be Samhain, the Celtic version in which Gwyn ap Nud rounds up the ghosts from the previous year and drags them down to the underworld. Just because it seems cool. If not that, then possibly the chinese Feast of the Hungry Ghosts, if I've translated it correctly, because it's more a time of reminiscence than of dying, or of autumnal festivals.
(if you are an expert on a particular form of celebration on which somebody mistook a detail, or confused with an entirely different holiday, I think it would be helpful to state so. Not, however, if one has only knowledge from passing references.

No worries about the specific sections and their attributes...I might have made too many, and realize that it may be confusing. But this is, indeed, the right place.

In respects of the thread, I know that there are many different variations and practices which resemble Halloween, and believe them to be, in the end, of the same concepts, much as I would always argue about different religions.

Although I do not celebrate it, I am quite fascinated by ''Walpurgisnacht'' (Witches's Night.) a German holiday where witches gather together to welcome the arrival of Spring, and symbolizing this by making huge bonfires.

Originally a Celtic holiday frowned upon by even those whom accepted and believed in the practices of Samhain, it was also celebrated by the Vikings.

Only a recognition today, I have decided to include this here because of such; it does not exactly pertain to the origins of Halloween or the variations and similarities thereof, but it WAS celebrated by Wiccans (Still is in modern Wicca, and modern Satanism.) because of the obscure alignment of the practice and its significance and impacts.

However, as I am not so well versed with exactitudes and the like myself, if there be an expert in the room...please feel free to correct me, as well.