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

Ever hear of the Milazzo Cage?

An unremarkable wooden wheel built into the side of one of Rome's oldest hospitals was part of a policy to reduce infant exposure.

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

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

An 18th-century post box used to alert the church of sick and ailing foreign pilgrims.

One of Rome's most picturesque and original bridges was also a popular choice for Grand Tour artists.

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

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

A rare example of a medieval house in Rome adorned with a melancholic inscription.

A deep mark on the remains of a Roman temple, believed to be left by a legendary warrior.

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

In Rome’s Jewish ghetto, a 200-year-old bakery still makes the neighborhood’s historic sweets.

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

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.

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

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.

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

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

Ancient ruins hidden underneath a modern luxury hotel.

A magnificent waterfall is also home to the remains of a Roman hydraulic engineering system.

A forgotten "city of water" underneath the famous Trevi district.