Castelnuovo, with its romanesque “Duomo” (Cathedral) and the Ariost Fortress, is the commercial and administrative centre of the valley, animated every Thursday, since 1430, by an open-air market. From the market-place, the provincial road leading to the Versilia area flanks the Turrite Secca, a typical Apuan Alps torrent, narrow in a gorge.
After a few kilometres, you reach the Lago di Isola Santa (Isola Santa Lake), where an uninhabited hamlet, with typical style buildings and stone slated roofs, lies on the banks. Continuing along the road, the scenery changes to the rock-faces of Monte Sumbra, with the "Marmitte dei Giganti", characteristic rock erosions caused by water on the stone.

At Tre Fiumi the principal road ascends to the Galleria del Cipollaio (Cipollaio Tunnel) leading to Forte dei Marmi and the Versilian Coast, along this road, at Levigliani it’s possible to visit the wonderful cave Antro del Corchia (for more info about opening time telefono 0584 778405 or www.antrocorchia.it); whereas, on the right, the road leads to Arni and the Galleria del Monte Pelato (Mount Pelato Tunnel) and the Passo del Vestito (Vestito Pass) and Pian della Fioba where a worthwhile visit is to botanic garden “Pellegrini”. From this height the view sweeps over the coast, the marble quarries of Carrara to the Golfo di La Spezia (La Spezia bay) and Portovenere.

On the return journey, a little before Isola Santa, you can find the road leading up to Capanne di Careggine and the Maestà della Formica then down to the Careggine village situated on a plateau where you can enjoy a splendid panorama. Here in the winter season, you can ski and during the other seasons you can walk along fascinating paths and tracks in century old chestnut woods. When you arrive at Poggio, you must visit the small romanesque church S. Biagio.