Today, watching joggers and bikers might be the 21st century equivalent for visitors sampling history along this venerable road. You might even want to do your people-watching as the Romans do it - from the vantage point of an osteria, a roadside inn with a garden for dining on capretto, spit-roasted young goat, the local specialty.
The Appian Way was begun as a military highway in 312 B.C. by the statesman Appius Claudius. Paved with huge lava blocks in a bed of crushed stone cemented with lime, the road was wide enough to allow two chariots to pass. Soon it stretched 350 miles to the Adriatic port of Brundisum (now Brindisi) at the heel of Italy's boot.
Alongside it ran the Claudian aqueduct, supplying fresh water for Rome's gardens, fountains and the baths that could accommodate 3,000 bathers at a time.
Romans built villas, tombs and mausoleums against a backdrop of the purple Alban hills. Under ivy-draped walls, early Christians dug catacombs, which were tunneled graves for their dead.
Helmeted Roman legions marched off to war along the road, trading caravans passed through, and visiting princes paraded, riding elephants and bearing gifts of caged lions for the circus games.
A modern-day tour of the Via Appia Antica might start at the end of the Forum, just beyond the Circus Maxentius where charioteers raced seven times around an obelisk cheered by spectators in 10 tiers of stone bleachers.
Near here, weary travelers beheld Rome's golden milepost - where all roads led. Soon the pleasant road, shaded with cypresses and umbrella pines, passes scattered piles of eroded bricks that once were grand mausoleums.
A short distance brings the traveler to the dome-shape ruins of the ornate tomb of the noblewoman Cecilia Metella. She was the daughter-in-law of Marcus Crassus, who shared the triumvirate with Pompey and Julius Caesar. In Childe Harold's Pilgrimage, Lord Byron muses whether she died young and fair or old and wise.
Pope Urban VIII ripped up the marble floor of her tomb to build the Trevi Fountain.
At Porta San Sebastiano is the Church of Domine Quo Vadis. Legend says St. Peter, fleeing Nero's persecutions after the great fire, saw a vision of Christ heading toward the city.
"Lord, where goest thou?" ("Quo vadis?") he asked, and the vision replied, "To Rome to be crucified again."
At Porta San Sebastiano is the largest and best preserved of the fortified gates in the Aurelian Wall that embraced the seven hills of Rome for more than a thousand years. The twin gate towers house a small museum of wall artifacts. You can walk along the top of the wall for postcard views of the Appian Way and the distant Alban Hills.
Beyond the narrow ancient gate, the road dips into a valley covering a five-level maze of catacombs where thousands were buried. Rome has more than 60 catacombs, some not yet fully explored.
The two most important catacombs open to the public along the Appian Way are St. Sebastian and St. Callixtus, where most of the early popes and many martyrs were buried.
Walls and ceilings have paintings and frescoes of early Christian symbols such as the fish, the dove and the anchor, and scenes from Scripture such as Jonah swallowed by the fish, Daniel in the lions' den, the raising of Lazarus and, most often, the Good Shepherd.
Over the centuries, pilgrims scratched graffiti invocations to Peter and Paul on the walls of San Sebastian. The two apostles were united in death when their bodies were reburied together during the persecutions of the Emperor Valerian.
A year ago, archaeologists exploring the Catacombs of St. Peter and Marcellinus uncovered a chamber with more than 1,000 skeletons arrayed in elegant togas, some interwoven with gold thread. Tests are under way to determine whether the neatly piled remains were victims of mass executions or a deadly plague late in the first century.
The catacombs were dug by grave diggers who, by the dim light of oil lamps, tunneled out the labyrinthine galleries, carrying away the earth in baskets and using lucemaria - skylights or air shafts - for ventilation.
In these subterranean passages, the early Christians hid out and held services during times of severe persecution. A millennium later, when the great gothic cathedrals were rising across Europe, grave robbers plundered the underground tombs for relics.
Rome's oldest golf course, the Circolo del Golf di Roma, is where senators, diplomats and movie moguls tee off along lush fairways framed by the arches of the Claudian aqueduct.
It was also along the Appian Way that Paul of Tarsus, a prisoner in chains, who had come to plead with the Emperor Nero for his life, had his first view of Rome, the gilded temples and palaces shimmering in the distance.
IF YOU GO
APPIAN WAY: www.parcoappiaantica.org or 011-39-06-512-6314. Web site offers information on tours of the Appian Way; how to get there by public transportation, bike or foot; opening times for monuments and museums, and other information. Visitor center is at Via Appia Antica 42 (open Monday-Friday, 9:30 a.m. to 1 p.m., 2:30-5 p.m.).