Dun Bhaloir, or Balor's Fort, is the dramatic eastern end of Tory Island: a narrow headland cut off by embankments and surrounded on three sides by high Atlantic cliffs. Archaeologically it is slight, but as a place it is enormous. The walk out gives you the serrated ridge of An Eochair Mhor, surf below, and the hard edge of Donegal weather.
In Irish mythology, Balor of the Evil Eye was a leader of the Fomorians, and Tory is one of the places linked to his stronghold. You do not need the legend for the headland to work, but it gives the cliffs a proper old darkness.