Italy has 49 UNESCO world heritage sites with 10 in southern Italy (as of 2013). Southern Italy's world heritage sites include city centers, palaces, caves, trulli, and archaeological sites. Cities and sites are listed in the order in which they were inscribed by UNESCO starting with the sassi of Matera in 1993. For more about southern Italy, see Top Places to Visit in Southern Italy.
Matera, one of the most breath-taking places I've been in Italy, is an unusual town in the interior of the Basilicata region known for the sassi, a huge troglodyte settlement. The cave houses, dug out of the tufa, were inhabited from Paleolithic times until the 1950's. Today the cave houses have been revived and you can even stay in a Sassi hotel. There are also fascinating Rupestrian churches carved out of the ravine.
The historic center of Naples is packed with interesting narrow streets, churches, and outstanding monuments. Castel dell'Ovo, the oldest castle in Naples, sits in a beautiful position on the promontory. The Spaccanapoli district is a string of narrow, winding streets that's mainly a pedestrian zone in the historic center. There are many tiny and interesting shops. Via San Gregorio Armeno, one of the streets in the center, is known for its artisan workshops making nativity scenes.
Trulli are unique architectural structures with conical roofs made of limestone slabs. Trulli dot the landscape of the Itria Valley in Puglia but there are more than 1500 trulli in the town of Alberobello. Even with the crowds, I was awed by the site of the trulli zone. Many trulli are still lived in but some have been converted to restaurants, shops, and hotels or holiday houses. I stayed in a trullo in the trulli village of Grand Hotel La Chiusa di Chietri outside Alberobello.
Pompeii is one of Italy's best known archaeological sites. Both Pompeii and Herculaneum were towns engulfed by the eruption of Mount Vesuvius in 79AD and much was preserved beneath the lava flow. Both places can easily be visited as day trips from Naples. Also included in this site are the wall paintings of the Villa Oplontis at Torre Annunziata.
Italy's scenic and rugged Amalfi Coast is one of Italy's most beautiful stretches of coastline. The picturesque medieval villages dotting the coast hold important architectural and artistic works. In its heyday in the middle ages, the town of Amalfi was one of the four major maritime republics.
The Cilento area south of Naples has been important since prehistoric times. The Greek temples at Paestum are well-preserved and Velia is also an important classical site. The National Park of Cilento and Valle di Diano is Italy's second largest national park, reaching from the coast to the foot of the Apennines. It's in the southern part of the Campania region and western Basilicata region. Also in the area is the Certosa of Padula, an important charter house.
The Sanctuary of the Archangel Michael on Puglia's Gargano Promontory is part of the UNESCO World Heritage Site, Longobards in Italy - Places of the Power, an inscription that includes 7 important Longobard churches and monuments dating from the 6th to 8th centuries. Also in southern Italy, the Church of Santa Sofia in Benevento is part of this inscription.