From Boí along the road to Caldes (L-500) up to the parking lot of Cavallers. The itinerary takes us to the upper basin of the Caldes riverside. The livestock that goes to graze at Val d’Aran also uses this route to cross over to Colomers by the Port of Caldes. Once we can see the waters of Cavallers, we take a well kept trail along the edge of the dam, which constitutes a sight varying in beauty according to the time of the year. Once at the end of the reservoir there is a slight climb up to the Plateau of Riumalo. After that comes the steepest ascent, known as Llastres de la Morta (literally “the ballasts of the deceased”). We will then wind along the ice polished rocks until we see Estany Negre right underneath us.