A nineteenth century map in a North Wales town hall could unravel one of Celtic historys most enduring mysteries the location of the legendary Land of the Dead. The map at Llangollen town hall could potentially rewrite the history of one of the worlds greatest hidden landmarks, a Celtic history expert claims. According to Welsh mythology the Land of the Dead or Annwn: Celtic Underworld was ruled over by Gwynn ap Nudd. He escorted the souls of the dead there, and led a pack of supernatural hounds. For centuries this place has believed to be pure fable.