The most famous dwellings of all are the Sassi in Matera, which is just across the state line in the Basilicata region. Below the modern town and built on the side of a steep ravine, two whole neighborhoods of single-room cave dwellings and rock-hewn, frescoed churches were inhabited first by hermits and then by families until the 1960s. While some are now trendy hotels and restaurants, they still look so authentically ancient that Mel Gibson filmed scenes here for "The Passion of the Christ."

CITIES AS ART — Art is not a masterpiece in a museum but a whole downtown in Valle d'Itria cities like Locorotondo or, by the coast, in Bari, Ostuni and Lecce.

Locorotondo is a round nest of a village where everything is white except for the bright splashes of red flowers that overtake its wrought-iron balconies. Ostuni is even more blinding, though a sea breeze caresses you as you hike up and down its steep inclines and marvel at the sculpted baroque portals on its whitewashed houses.

But you haven't seen Baroque in all its theatrical, indulgent, luxuriant excess until you've spent an evening among the wreaths of fruit and the pinup women sculpted on the golden limestone churches and palaces of Lecce.

By comparison, the medieval downtown of Bari is austere, centered on the Basilica di San Nicola, built between the 10th and 12th centuries to honor its patron saint (yes, it's the real St. Nicholas, "Santa Claus").

The busy port city is trying to overcome its dangerous reputation, but the only person that chased us in the narrow alleys was a grocery store clerk with a cold bottle of water, concerned that ours had become too warm as friends and I waited for another clerk to make our sandwiches.

ART GEMS — Medieval masterpieces are everywhere on the eastern coast, beginning with the inscrutable Castel del Monte. We know the octagonal castle was built by Emperor Frederick II, one of the most powerful men in the Middle Ages, in the early 13th century. But nobody quite knows why.

Isolated on a small hill, it lacks both the architecture and the location for a military fort, and it's way too imposing to be a pleasure palace. The most evocative hypothesis is that it was an intricate symbol, built around the magic intersection of astronomy, mathematics and the Christian faith.

Traveling south, the Romanesque cathedrals at Trani and Otranto seem to rise from the sea. The latter's floor is covered by a mosaic from 1165 representing the tree of life, a hopeful message in the site of a massacre — a chapel houses the remains of the 800 citizens who were slaughtered in the church where they had fled an assault by Islamic armies in 1481.