Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

An abandoned Roman salami factory has found new life as an art space home to 200 squatters.

A hospital where antique dolls are given new life.

A fairy tale castle in modern Rome.

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

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

A statue representing a lost Roman profession that was vandalized for centuries.

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

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

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

This large, circular tomb is the final resting place of the first emperor of Rome.

Gods clash with machines in a power plant regenerated as a museum.

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

The studio built by fascists in the hopes of "reviving the film industry" with the occasional propaganda film opportunity thrown in.

One of the most important yet well-hidden museums dedicated to the history of medicine.

This hill made entirely of ancient Roman jars was simply a garbage dump to the people of the time.

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

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

A collection of objects supposedly singed by the hands of souls in purgatory.

This beautiful park on the outskirts of Rome protects the ruins of two colossal ancient aqueducts.

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

2300-year-old Roman road connecting the empire.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

This hidden Art Nouveau courtyard is an opulent feast for the eyes.