The stretch of territory called "Upper Valdarno", delimited by the right bank of the river Arno and by the hilly formations introducing Pratomagno, is characterized by geological structures of particular charm and beauty formed by stratified sand, clay, and gravel reaching one hundred meters of height and by a series of diversified shapes alternating with deep ravines. These structures, called Balze, are not only the result of the dismantlement of the ancient sediments by the atmospheric agents, but they have also been shaped by the presence of man.