Also in Castelnuovo is the marvellous Fortezza di Mont'Alfonso, the most impressive fortress in Garfagnana, built in the 16th century by Alfonso II d'Este. It stretches 60,000 square metres with a 1,150 metre wall, seven ramparts and two entrance doors.
You should also visit the Verrucole Castle in San Romano, a less impressive but still extremely charming fortress. It’s an example of medieval military architecture that was transformed in the 16th century with the addition of ramparts and has been recently restored to its original beauty. From here, you can enjoy sweeping views of the whole valley and the Pania di Corfino Nature Park.