The meaning behind this triumphal Roman arch was a mystery until the early 20th century.

This small church was constructed over the ruins of three temples dating to the Roman Republic.

A colossal aqueduct from the second century B.C., deeply hidden in a gorge on the outskirts of Rome.

Legend has it that this bronze orb, which sat atop an ancient Egyptian obelisk, once held the ashes of Julius Caesar.

According to local folklore, this Roman sepulcher was once a throne for the Devil.

A rather vulgar example of the transition from Latin to the Italian vernacular.

Known for centuries as the famous Roman emperor's burial place, this monument is actually something else.

These hut foundations are believed to be the residence of Romulus, founder of Rome.

This one-of-a-kind Roman arch is not actually dedicated to the god Janus.

A fortified medieval basilica on the Caelian Hill preserves extraordinary frescoes and one of Rome's most beautiful hidden cloisters.

Remnants of a 4th-century church with vivid medieval frescoes and ancient sarcophagi hide beneath this old basilica.

Stone memorial that's said to predict the death of the pope and the site of the Cadaver Synod.

The ruins of an abbey believed to have been founded by Charlemagne in the 9th century.

This park on the outskirts of Rome boasts two ancient Roman aqueducts and a medieval tower.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

This gallery commissioned by Cardinal Spada is known for its magnificent optical illusion.

In the early Roman Empire, people deemed traitors and criminals were tossed to their deaths from this rock.

This ancient trail climbs the mountain where a Latin League cult worshipped Jupiter, its main deity.

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

This is the oldest Roman-made bridge in the city still existing in its original state.

This curious, round temple is the oldest still-standing marble building in Rome.

This ancient market is often referred to as the oldest shopping mall in the world.

The best preserved Paleochristian basilica in Rome hides a number of oddities and secrets.

An Italian ghost town that fought obscurity, until a mysterious illness brought it to its knees.