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

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

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

Museum dedicated to literary greats of the Romantic Period is also the home in which Keats met his untimely end.

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

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

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

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

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

2300-year-old Roman road connecting the empire.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

The yawning maw of this pagan visage is said to bite off the hands of liars.

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

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

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

A monument to the conquistador became increasingly controversial in the very city that he founded.

A Christian monastery stands on what was once a holy Incan temple.

The retired vessel is South America's first floating museum.

This is why we can't have nice things on the Incan Trail.

An Inca spa, military outpost or maybe… both?

Situated on a sacred Inca site, this 16th-century cathedral took nearly 100 years to build.

This geometric feat is a testament to the Incas' mesmerizing architectural abilities.

Visiting dignitaries and Hollywood stars once stayed at this 1920s hotel, alongside ghosts that are said to haunt its corridors.