As one of the most haunted cities on earth Edinburgh offers a Halloween experience as authentic as it can get. Come and explore the subterranean labyrinth of 17th century streets, or take a ghost tour through the medieval streets and learn of grave robbers and the murderous activities of Mr Burke and Hare. In the evening there are ghost tours, masquerade and fancy dress balls, dinner & Ceilidh Balls, fire festival and so much more! Here are a few websites for inspiration.
http://thisisedinburgh.com/blog/things-to-do-for-halloween-in-edinburgh/
https://www.thedungeons.com/edinburgh/en/plan-your-visit/halloween.aspx