This medieval bridge is situated near the 'Hermitage of Rosia' and the Montarrenti castle, and it's simply called 'of the Pia' (nothing to do with the famous Pia dè Tolomei nominated by the poet Dante Alighieri on his 'Divina Commedia' - see also Castel Pietra) that cross with its unique arch the Rosia stream. It was one of the most important point of the ancient 'Massetana' road that in the Middle Age connected Siena with Massa Marittima and the mines of the Metaliffere Hills. The aspect of the bridge, although sure reconstructed in the 16th century, goes back to the first years of the 13th century. It is Still today solid but can be crossed only by foot and making much attention because it's now lacking of the parapets.