A picture made of lake and hilly landscapes completed by some human activities characterizing them, and at the same time an irreplaceable rest place for the migratory avifauna and a vital place for some important fish species. It is the unmistakable historical landscape reproduced in the paintings by several 15th century artists. Its delicate hydrologic and biological balance has always required its protection by man, which is still today necessary to the survival of the resource.