How could accounting books be so fascinating? The ones from the State Archives in Siena are veritable works of art and tell some interesting stories.

We have a look at two important medieval manuscripts in the State Archives. They are the original Constitution of the Republic of Siena. Alberto Angela gives us some fascinating facts concerning it that reaffirm how wise the rulers of that republic were.

The Siena Cathedral is large, but it was supposed to have become much, much bigger. Alberto Angela tells the fascinating story.

Alberto Angela explores the Piccolomini Altarpiece with sculptures by Michelangelo, and the beautiful frescoed Piccolomini Library within the walls of the Siena Cathedral

Alberto Angela focuses on one of the floor inlays depicting the story of Siena according to tradition. Siena shares a city symbol with Rome.

The Siena Cathedral is one of the most notable examples of Italian Romanesque-Gothic cathedrals, and is well worth a visit, for both the beauty of the exterior and the unique marble artwork on the interior.

Alberto Angela brings medieval Siena to life, with the help of some breathtaking aerial shots.

We are now in the heart of Italy: Tuscany. One of the most beautiful and important cities in Tuscany is Siena with its very particular piazza.

Alberto Angelo tells us the fascinating story of how trulli are built. Some of the most characteristic trulli can be found in Alberobello.

We visit the land of the trulli, curious dry stone huts. Alberto Angela gives us some background about these unique dwellings.

As opposed to the classical palaces of the powerful, with their throne rooms and great halls, Castel del Monte has some smaller and more intimate spaces, conducive to more personal encounters. Over the centuries, the castle was exploited in different ways, well into modern times.

Alberto Angela takes us inside Castel del Monte and helps us imagine what it might have looked like when it was "alive." He uses the term piano nobile, which indicates the floor of a mansion where the noblemen or landowners lived, as opposed to the floors where the servants' quarters and kitchens would have been.

Wonderful aerial photography shows Castel del Monte and its crown-like octagonal shape. Frederick II was particularly fond of the castle because it was an ideal location to hunt small game with his falcons.

The first stop is Italy's easternmost point, the Punta Palascìa and its 19th century lighthouse. Alberto Angela then shows us another site in the Apulia region, Castel del Monte, a breathtaking crown-shaped castle built by Frederick II in the early 1200s.

We say goodbye to Agrigento's Valley of the Temples and get a close look at the awesome Riace Bronzes in Reggio Calabria. The two life-size Greek bronzes date to the 5th century BC and were discovered off Riace by a scuba diver in 1972.