Barranco de Lumos is located in Sierra and Canyons de Guara Park in Aragon province of Spain. This barranco has a slot section in conglomerate formation so narrow that author call it "rasp slot". In this torture passage or fat man misery you have to remove your pack and walk side way. Another particularity of this slot canyon is you can enters inside it by two differents sloted hill side drainage (impluvium). Access to the barranco is close to Collado San Capraso (San Capraso pass) on the road Ainsa-Colungo between KM post 8 and 9. Two ropes about 25 meters long is needed to rappel inside.