Casteal Grugaig Broch or Dun to give it its full name. A really fascinating structure with circular hollow walls including a number of chambers and staircases. No-one really knows exactly when this and similar Brochs date from, nor what their true purpose was. Although possibly defensive in character, in this case would have been very vulnerable to firing from above as the 'vitified forts' were. Maybe the seat of a local chieftain fairly secure of his territory as long as invaders from over the sea could be spotted in time and for that it is ideal. I also have more photos of some of the chambers and openings, please contact me by leaving a message for these.