Monte Perdido is the biggest calcareous massif in Western Europe. It is in the National Park and is known as the Three Sorores (Treserols).
Treserols is an enormous peak of spectacular morphology and unique forms formed by three huge peaks: The Monte Perdido (3355), the Cilindro de Marboré (3328) and the Añisclo Peak (3263). Among them, there are about twenty peaks over three thousand metres. Those peaks are both the origin and the feed of all the rivers that cross the valleys in Ordesa and Monte Perdido National Park.
In these high areas stands out the north summit between the Gabietos and the Three Sorores, a series of peaks and walls with more than three thousand metres where the famous Roland’s Breach is located. This Breach is an enormous gap of 2807 metres high, serves as natural border crossing and is a place full of legend. It has been the crossing point for smugglers, fugitives, refugees, hunters and shepherds throughout history.