The Monte Perdido Massif is the highest limy mountain in Europe. It is not surprising that we find myriad of caves and pits inside, some of them among the deepest ones in the world, such as the Arañonera's system (35km long and 1179m deep).
It is the recreational sport of exploring caves, pits, shafts, chasms, underflowing streams, etc. using specific techniques and equipment. A good knowledge of diverse techniques is required, from climbing to diving.
Among the several pit caves in Monte Perdido, we find the second major caving area in the world, Fuentes de Escuaín (1150m deep and 10790m. long); and the highest caving area in Europe, Punta de las Olas. Therefore, no wonder Sobrarbe is a privileged location among caving systems worldwide.