The second-highest train station in Europe.

The site of Austria's biggest concentration camp now honors its victims.

Two nations form a rare four-sided border at the peak of a mountain, philosophical questions result.

This series of underground chambers contains Europe's largest subterranean lake that is slowly drained each day.

From carts to cars, this leftover Roman bridge in France has managed to survive for centuries.

A formerly opulent Italian village is now a crumbling ghost town that no one really knows what to do with.

A macabre anatomy museum tucked within an old Italian hospital.

A dilapidated psychiatric facility on the outskirts of Milan where electroconvulsive therapy was developed and Napoleon once lived.

An abandoned village, frozen in time by the threat of a landslide.

Bell tower juts out from a village buried under a lake.

Once the hunting reserve of a noble family, this is one of the few remnants of Pleistocene planitial forest in northern Italy that still stands.

This uniquely designed bridge served as the city gate for Comacchio.

When a massive landslide hit one of the world's tallest dams it created a tragic environmental disaster.

Old batteries and frog skeletons reside in this lakeside monument to Alessandro Volta.

A domed disco abandoned since the '70s now attracts artists and explorers under its unique roof.

This Tuscan lake hides a 13th century town that is still visible when the water recedes.

Explore the quarry where the marble was sourced for Michaelangelo's David.

The bright red cars take travelers through breathtaking Tuscan scenery.

Mexico's astounding mummy museum with "the world's smallest mummy."

This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

This stunning natural double arch, the largest in the Alps, went undiscovered until 2005.

Trek up this glacier before it disappears.

A suspended footbridge allows for traversing this gorge carved through the French Alps.

A medieval military street hidden beneath a charming French fishing village.