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

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

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.

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.

Alberto Angela shows us a volume from 1554 that bears witness to one of the most dramatic moments in Sienese history. We then go on to the beautiful city of Pienza.

The Republic of Siena ends in the 16th century and power goes to Florence, where we go next, to see some of the architectural wonders there.

This video focuses on one of the most famous artists of all time, Leonardo da Vinci. In particular, we start looking at one of his greatest masterpieces, the Last Supper.

We look at Leonardo's Last Supper from close up — the details, the symbolism — but also from the refectory floor, seeing how Leonardo's genius made the fresco part of the room itself.

Two geniuses left their indelible marks on civilization: Leonardo with the Last Supper and Michelangelo with his David.

This episode will take us to Umbria. We start with one of the most beautiful cities in the region, Assisi, a city that's practically synonymous with the Franciscan monastic order and its founder, Saint Francis.

People often wonder how the Basilica of St. Francis could be as imposing and rich as it is, when the saint to whom it is dedicated had taken an oath of poverty. Alberto Angela explains this and other contradictions.

What did Saint Francis look like? There are clues in a fresco in the lower basilica of the church dedicated to him in Assisi.

We move from the lower basilica to the upper one, which has an entirely different feel to it. Here, we are surrounded by a show of light and color in colorful frescoes and stained-glass windows.

Alberto Angela points out how realistic Giotto's frescoes are compared to earlier ones. He also mentions the important fact that Saint Francis composed one of the first poems in the vernacular

We move from Umbria to Tuscany and visit the evocative ruins of the abbey of San Galgano. Next will be Pisa, a prime example of how Tuscany, in medieval times, was experimenting with very "modern" ideas.