Declaration of the Lake of Truchillas as a Natural Monument Historical milestone · Truchas, La Cabrera, León Image of Truchas, not of the place itself. Decree 192/1990, of 11 October, declared the lake of Truchillas and its surroundings a natural monument, in the municipality of Truchas, for the value of its glacial modelling. Located in the lower part of the Eria valley, presided over by the Vizcodillo peak - which reaches 2,121 metres at the boundary with the province of Zamora - the protected area preserves close to a dozen well-developed glacial cirques and fine examples of lateral and frontal moraines in the vicinity of Vizcodillo itself. 11 de octubre de 1990 Photo: Xemenendura (CC BY-SA 4.0) What to see and do in Truchas