High in the clouds of San Marino sits an ancient tower with some curious prisoner graffiti.

The San Marino-Rimini railroad was short-lived but this tunnel once provided shelter for hundreds of refugees during World War II.

Where members of the Crossbow Corps of San Marino demonstrate their skills.

The smaller of the three towers of San Marino is a former prison inaccessible from the ground level.

The only Shinto shrine in Europe that has been officially sanctioned by Japan.

A wild west land agreement was etched right onto this historic Idaho stone.

This tiny museum's sizable collection is jammed into a former underground public toilet.

The ruins of the "place of the cloud snake" sit in the middle of an urban environment.

Hidden for more than a century, the grave of the Conquistador remains forgotten behind these church walls.

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

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

Hidden within this iconic mountain are a set of World War II bunkers once used by German forces.

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

This park on the outskirts of Rome boasts two ancient Roman aqueducts and a medieval tower.

This ancient trail climbs the mountain where a Latin League cult worshipped Jupiter, its main deity.

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

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

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

Roman-era ships unearthed...

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

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.

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

An Italian ghost town that fought obscurity, until a mysterious illness brought it to its knees.