The granite of Zarzalejo at El Escorial Historical milestone · Zarzalejo, Sierra Oeste, Madrid The municipality's quarries supplied the ashlar for the building of the Monastery of San Lorenzo de El Escorial during the two decades the work lasted (1563-1584), and from them also came a good part of the stonemasons who raised it. 1563-1584 Photo: LBM1948 (CC BY-SA 4.0) What to see and do in Zarzalejo