Castle of Alba Monument · La Robla, La Montaña de Luna, León Image of La Robla, not of the place itself. Fortress located on the Peña del Castillo, near Llanos de Alba, in La Robla, overlooking the valley of the río Bernesga and the road that linked León with Gijón over the Pajares pass. Built by Alfonso III of Asturias in the 9th century, probably on an earlier Roman settlement, it retained two defensive lines with a wall two hundred metres long and three metres thick. It played a key role in the revolt of Alfonso III's sons: in 910 Queen Jimena handed it over, together with the castles of Luna, Gordón and Arbolio, to her eldest son García I of León, which forced the king's abdication. In 997 it withstood the attack of Almanzor, and passed through the hands of various magnates until the Treaty of Tordehumos of 1194 returned it to the kingdom of León. Now in ruins and difficult to reach, it is declared a Bien de Interés Cultural (Spain's highest level of heritage protection). Photo: FreeCat (CC BY 2.0) What to see and do in La Robla