Flour mills of the Guadarrama River Curiosity · Los Molinos, Cuenca del Guadarrama, Madrid Image of Los Molinos, not of the place itself. The village owes its name to the river's water-powered mills: a licence of 1546 authorised Álvaro de Mena to build a penstock mill, and at least three mills supplied flour to the works on the monastery of El Escorial. Photo: Arturo Francisco Barbero (CC BY-SA 4.0) What to see and do in Los Molinos