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

This basilica is dedicated to two saints, one of which is known more for his famous quote.

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.

A massive marble foot is tucked away in a small alley near the Pantheon.

Romans decided this 16th-century "talking statue" was so ugly, they named it after a primate.

One of Catholicism's four major basilicas has a series of papal portraits that are said to predict the end of the world.

Also known as the Square Colosseum, this building is a prime example of fascist-era rationalist architecture.

Its interior is adorned with some of the best examples of early Christian mosaics.

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

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

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

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

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

Ancient ruins hidden underneath a modern luxury hotel.

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

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

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

A treasure trove of Renaissance-era funerary art in a Roman church built on top of Nero's grave.

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

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

More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

The spot where the fascist dictator made some of his most famous speeches including declaring war on Britain and France.

Installed in an act of one-upsmanship, the annual sundial in this church is also a symbolic victory for the Gregorian calendar.