The primary route to Greece and the East, this gateway is part of the Aurelian Wall, which was a defense system dating back to the third century. The Appian Way is the Roman Republic's oldest highway, with sections still in use today. Take a relaxing stroll along the restored wall and enjoy a matchless view of the surrounding area, little of which has changed from when the Apostle Peter traveled through Rome on foot. BUS: 118 from Circo Massimo metro station or the hop-on hop-off Archeobus from in front of Stazione Termini (see www.trambus.com)

Built in 315 AD to commemorate the emperor's triumph at the Battle of the Milvian Bridge in 312 AD. The battle marked a turning point in the history of Rome and Christianity, as the skirmish was closely related to Constantine's conversion and his issuance of the Edict of Milan. The edict provided Christianity with legal status that was previously unavailable during several decades of intense persecution.

Built in the third century as part of Rome's defense system, this massive fortification wall is a must see. The wall was commissioned by the Emperor Aurelian after the city's previous structure was in ruins. The wall has undergone significant restoration, and the best-preserved gate is at the Appian Way. At Via Porta San Sebastiano 18 there is a small museum open Tuesday - Sunday, 9am-2pm.

This immense facility is largely in ruins, although certain sections are still standing and house the National Roman Museum. Completed in 306 A.D., these were the largest of the imperial baths and remained in use until the water supply was cut off by the Goths in 537 A.D.

A statue of the Archangel Michael stands atop the Castel Sant'Angelo and is the source of the castle's name. It was originally built in the second century as Emperor Hadrian's mausoleum. Visitors, especially kids, will be charmed by the draw bridges, trap doors, ditches, canons, dungeons, weapons and papal apartments here. The terrace of the castle offers a splendid view of the city in all directions. There is also a charming café. BUS: 80, 87, 280, 492. METRO: Lepanto