The sunken structure looks like the victim of a catastrophic flood.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

This outdoor gallery of graffiti-covered walls pays homage to the past, present, and possible future of street art.

The world's first combination ski slope and power plant.

Incredible labyrinth of man made caves.

An icy lake tucked among jaw-dropping alpine panoramas.

On the grounds of a former estate in Burgundy stands an elaborate temple that is modeled after the first Tibetan Buddhist monastery.

The abandoned Japanese amusement park once loomed as a dystopian Disneyland.

Known as the "Valley of the Moon," this Jordanian wadi is one of the most amazing desertscapes on Earth.

Perched above the bustling town of Kerak is a sprawling, ruinous castle that has witnessed nearly a millennia of Levantine history.

An ancient capital city that dates back 3,000 years and harbors many surprises.

A ghost village sits atop a mountain within Jordan’s largest biosphere reserve.

The beautiful baroque library of the Hapsburg empire.

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

Two gravestones clasp hands over the religious divide.

This giant urban staircase was built to keep the city's brave fighting men from getting waylaid in the red light district.

This historical Netherlands fortress still bears the marks of its single siege.

This centuries-old gothic monster has been converted into a sprawling, glossy bookstore.

Rare wooden escalators lead deep down into an otherwise staggeringly monotonous tiled tunnel.

This ghost town in Belgium will lose its street art when it ceases to exist.

This narrow Ghent alleyway is an officially sanctioned street art tunnel.

A Museum of Psychiatry in a still-operating mental institution.

The history of occult science is turned into a creepshow at this lurid Prague tourist attraction.