Up until about ten or so years ago, nobody here knew very much about Halloween, and didn't celebrate. Now they do, but without the trick-or-treat. Here it has now become known as Noć veštica (night of the witches), but actually the holiday has little to do with real horror or witches. November 1st in some countries is All Saints' Day. People in those countries visit graveyards where loved ones who have passed on are buried. The day before, October 31st, was believed to be the day when the dead returned to earth. Bonfires were lit to keep them at bay. Children eventually would dress up as ghostly figures and go door-to-door 'reciting Trick or Treat,' and be given sweets. Otherwise, they may play pranks on the stingy homeowner.
For a really good read about this originally Celtic 'holiday,' please read this on History Channel's link, THE HISTORY OF HALLOWEEN.