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

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

This ancient Roman arch misled treasure hunters for centuries.

The remains of this 2nd-century Roman temple are incorporated into a modern building.

A monumental fountain in Rome features a large statue of Moses that has been criticized for centuries.

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

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

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

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

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

The only remaining arch of the oldest stone bridge in Rome stands in the middle of the Tiber.

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

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

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

This hydrochronometer was invented by a Dominican monk and is a prime feature in this garden.

Ancient ruins hidden underneath a modern luxury hotel.

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

Brass cobblestones mark the places where individual Holocaust victims were taken from their homes.

A huge enchanting public park just outside the ancient walls of Rome.

The martyr's wax-enhanced skeletal remains lie preserved in a glass case in the Santa Maria della Vittoria in Rome.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

The skull of the patron saint of lovers lies in the Basilica di Santa Maria in Cosmedin—maybe.