The Diógenes mines Historical milestone · Mestanza, Sierra Morena, Ciudad Real Image of Mestanza, not of the place itself. The working of argentiferous galena known as the Diógenes mines sustained the district's economy for decades and closed definitively in 1979. With it there died out an activity that had drawn in companies and outside labour. 1979 Photo: LBM1948 (CC BY-SA 4.0) What to see and do in Mestanza