One of the most characteristic landscapes in Tuscany, the Balze del Valdarno are the astonishing result of geological phenomena that are still ongoing, leading to the constant erosion of the sediments of a large dried-up lake from the Pliocene era. These natural sculptures fascinated Leonardo da Vinci, who depicted them in some of his most famous works. Today they are the protagonists of evocative itineraries immersed in nature to be travelled on foot and by bicycle.
The phenomena of crumbling already began in the Late Pleistocene, about 100.000 years ago, when the crust of the great lake delimited by the Pratomagno massif and the Chianti mountains opened in Incisa Valdarno, causing the flow of water in the direction of Florence. This caused the lowering of the lake basin level and in the areas closest to Pratomagno. The tributaries of the great Tuscan River that descended downstream with more strength began to erode those sediments, forming the so-called “floats” (it. “balze”).
Approaching the characteristic vertical walls, you can recognize the geological passages through the succession of sediments: below the clays and sands deposited when the great lake was deeper, above gravels and pebbles transported by waterways when the lake basin was less sunken or dried up. This stratification creates natural spires and pinnacles of different shapes and heights, interspersed with deep gorges.
Walking along the ancient Via Setteponti, especially in the sections included in the municipalities of Loro Ciuffenna, Terranuova Bracciolini and Castelfranco Pian di Scò, you can admire up close some of these mammoth sculptures shaped by nature and observe how nature continues to modify them.
In recent years a network of routes has been created, which allows you to visit the protected area of Le Balze del Valdarno through paths on foot, by bike and on horseback, which are frequented by people of all ages, especially during the summer. One of the best known is the Sentiero dell’acqua zolfina, a six-kilometre loop itinerary that starts from the walls of Castelfranco di Sopra. Another suggestive route is the Strada delle Cave of about nine kilometers, which crosses the countryside of Terranuova Bracciolini and reaches the hamlet of Penna.
Two privileged points of observation of Le Balze are that of Piantravigne, a picturesque town in the Terranuova area lying on the edge of a natural overhang, and the Buca delle Fate, a short distance from the medieval village of Montemarciano, always in the municipality of Terranuova Bracciolini, which is a sort of natural amphitheater from where the great natural sculptures can be observed from below.
The landscape of Le Balze also suggested Leonardo da Vinci, so much so that in the backgrounds of masterpieces such as “Mona Lisa”, “The Virgin and Child with St. Anne”, “The Virgin of the Rock” and “The Madonna of the Yarnwinder” many scholars identify the unmistakable environment of Valdarno. Even in some juvenile paintings the artist represented environments that had many connections with those between Pratomagno and the course of the Arno.
Of the typical landscape of Valdarno Superiore, the Renaissance genius also speaks in the “Hammer Code” or “Leicester Code”, a manuscript that includes 36 sheets written between 1506 and 1510, where in advance of modern theories Leonardo perfectly understood the erosion processes that had shaped or were shaping the territory.