Tours of Roman Ruins in Italy

The Roman Empire at its farthest reaches stretched from Scotland to Egypt and from Mauritania to Babylon, so the empire's remains are scattered on three continents. But some of the best Roman ruins, including many World Heritage Sites, can still be found in modern Italy -- where it all began with the founding of Rome, traditionally dated to 753 B.C., and where the Western Empire finally collapsed under the weight of its own overstretch and the Ostrogoth invasions in 476.

The City of Rome

• The Eternal City is studded with Roman remains, peeking from behind churches and sprouting between busy roads. Walk the vast sprawl of the Forum Romanum, where ruins of ancient temples, basilicas and public buildings vie for attention and understanding. Perhaps no other place epitomizes the endless layering of Roman history better than the Temple of Antoninus and Faustina, where the baroque facade of the San Lorenzo in Miranda church appears to grow organically from the portico of the 2nd century Roman building. Nearby, the Colosseum stands as an embodiment of Roman pop culture, its brutal concrete arches a witness to the raw realities of carnage-as-entertainment. If you have time for more, tour the jumble of ruins on the Palatine Hill, other Imperial forums, numerous arches, as well as the Baths of Caracalla and the nearby Via Appia.

Ostia Antica

• Less than an hour from Rome by Metro and train, the ruins of Rome's ancient harbor of Ostia at the mouth of the Tiber were partially preserved in the river mud when the water silted up after the fall of Rome. The site gives a fascinating insight into the life of the ancient working port. Baths, temples, warehouses and dwellings still stand among the cypresses and pines -- some roofless and in ruins, others almost complete, with arches, mosaics and wall paintings. Don't miss the House of Diane, a well preserved example of an insula, a multistory tenement building of the type inhabited by most urban Romans.

Pompeii and Herculaneum

• The disastrous Vesuvius eruption of 79 A.D. buried the thriving cities of Pompeii and Herculaneum under volcanic ash and lava. The ruins -- excavated since the 18th century -- present a unique snapshot of life as it was in the commercial city of Pompeii, where rich and poor lived side by side, and the posher resort of Herculaneum. Everyday life was caught at a particular moment of sudden interruption, from the political graffiti to everyday objects abandoned as people tried to escape from the shower of hot ash. You will need a day to properly explore the sites; Pompeii is larger and Herculaneum more intact. Both are about a half hour from Naples, whether by car or on the Circumvesuviana train line.

Villas

• Villas, either country mansions at the heart of large estates, or hedonistic retreats from the cities, are scattered through the Roman countryside. Visit Hadrian's villa at Tivoli near Rome, an imperial residence covering more than 200 acres. Hadrian himself designed many buildings, and was influenced by Greek and Egyptian styles. Tivoli is 20 miles from Rome, or an hour's bus journey. On Sicily, Villa del Casale was both the focus of a great rural estate and a luxury residence of the owners. The mosaics there -- note the modern-looking bikini girls -- are considered the best Roman mosaics still in their original location. The site is near the village of Piazza Armerina, a two hour drive southeast from Palermo.