Landscape of the Sierra de Arcos in Estercuel Nature · Estercuel, Andorra-Sierra de Arcos, Teruel Image of Estercuel, not of the place itself. Estercuel sits on the slope of the Sierra de Arcos where the Order of Mercy founded the monastery of Nuestra Señora del Olivar in the 13th century, today a Monumento Histórico-Artístico (Spain's heritage designation in force between 1931 and 1985). Photo: jnerin (CC BY-SA 3.0) What to see and do in Estercuel