This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

An architectural marvel that spans the Arda River, and has stories of a haunted past.

This massive library holds what was once the largest book collection in the world.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

The fairy tale castle of the "fairy-tale king."

The giant skeleton sculpture is surprisingly well-traveled.

A fairy tale castle in modern Rome.

Architectureal fantasy quarter of Rome.

This centuries-old Italian chapel hangs midway down a sheer cliffside.

A stunning hermit's shrine on a steep rocky spur in Northern Italy.

Water and windows define this defensive Italian well.

This picturesque Umbrian city has a subterranean side that has long remained hidden.

A factory director designed what was the world's longest suspension footbridge in 1923 so his employees could get to work safely.

The forbidden island of the Tuscan Archipelago may still contain buried treasure.

A labyrinth of ancient tunnels hidden below the city holds the ruins of 2,500 years of history.

The glowing blue Nymphaeum of Emperor Tiberius.

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

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

Eco-village hidden in the foothills of the Alps that created a massive system of psychedelic underground temples.

Renaissance villa and gardens complete with a tormented colossus.

Abandoned medieval hill town.

A climbing route in the mountains of Italy’s Dolomites, built for soldiers during World War I.

Stalactites and stalagmites in a beautifully lit cave.

Mysterious tombstones thought to be remnants of Atlantis.