Foundation stone of the Pontón de la Oliva dam Historical milestone · Patones, Sierra Norte, Madrid Image of Patones, not of the place itself. The king consort Francisco de Asís laid the first stone of the dam on the Lozoya that was to supply Madrid. It was built by convicts from the Carlist wars in extremely harsh conditions, and its water reached the capital in June 1858. 11 de agosto de 1851 Photo: Ricardo Ricote Rodrí… (CC BY 3.0) What to see and do in Patones