One of the largest single-span stone-arch bridges in the Balkans looks like something straight out of a fairytale.

Perched on a spindly rock spire in a Greek archipelago, this lighthouse would make a perfect wizard's tower.

The second-highest village in Lazio has attracted artists for 400 years and is now a spectacular open-air art gallery.

Stare out over the lagoon and beyond from this 10th-century campanile on the island where the city of Venice began.

One of the highest mountain passes in Europe has been ranked among the best driving roads in the world.

When this funny little building went up in the 19th century, most people thought it would simply fall over.

The bright red cars take travelers through breathtaking Tuscan scenery.

Now an entertainment complex, the Lingotto building was once an avant-garde auto factory with a test track on the roof.

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

Erotic art covers the walls of the largest ancient pleasure palace.

This abandoned Brutalist treehouse is a hidden architectural relic.

Venice's island of the dead.

Dug as a secret royal escape route, the tunnel became a wartime bomb shelter and dumping ground for vintage cars.

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

This domed temple was built in a hidden cave mouth as a refuge for sinners seeking absolution.

Sitting on an Italian hilltop is this surreal fortress built by the mad inventor of electrohomeopathy.

Venice's "Island of the Mad."

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

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

These magnificent 240-year-old machines are considered distant ancestors of the computer.

A rare, flower-shaped example of Brutalist architecture in Switzerland.

Medieval irrigation channels built into the sides of mountains provided Valais with water for hundreds of years.

Museum of science fiction, utopias, and extraordinary journeys of the mind.

A historic observatory precariously perched at the "Top of Europe."