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

A burial vault located under Tiber Island in the middle of the Italian capital.

The "Great Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.

This small, ancient Roman temple was once a church dedicated to the patron saint of penitents.

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

Roman-style pizza al taglio arrives here with magnificent, crackly crust.

An enigmatic modern marker left next to a historic Roman site.

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

This subterranean shrine beneath a bike rental store celebrates the iconic Italian scooter.

An ancient Roman temple first dedicated to an emperor's wife is now a church.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

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

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

A wunderkammer of curious objects and intriguing art nestled within a hub of ancient Roman sites.

St. Francesca Romana, patron saint of drivers, resides in the church she founded.

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

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

A Nesting Doll of Churches.

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

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

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

Believed to be the remains of the lost Temple of Minerva, this nymphaeum has been known by its misnomer to this day.

An alchemist's “magic door” stands in the middle of a Roman park.

This Roman arch marks the location of an ancient gate at one of the Seven Hills of Rome.