Gorge of Los Arrudos Nature · Caso, Nalón, Asturias Image of Caso, not of the place itself. A narrow limestone gorge that opens above the village of Caleao, in the heart of Redes; the waymarked route that runs through it, of almost twenty-three kilometres and high difficulty, climbs between vertical walls up to the shepherds' huts of the sierra. Photo: Eduardo Diez Viñuela (CC BY-SA 3.0) What to see and do in Caso