Dam of El Villar Monument · Robledillo de la Jara, Sierra Norte, Madrid Begun in 1869 to a design by the engineers Elzeario Boix and José Morer and completed in 1882, it reached 50 metres in height and was the first curved-plan gravity dam built in Europe; it remains the oldest dam still in service of the Canal de Isabel II. Photo: LBM1948 (CC BY-SA 4.0) What to see and do in Robledillo de la Jara