An abandoned cable car station located on the Danube stands like a haunted house above the river.

This Hungarian stilt village is built in a lake that never freezes over due to the power plant that that uses it as a cooling pond.

The abandoned military base looks like a post-apocalyptic wasteland.

A small self-proclaimed micro-state located on a piece of disputed territory between Croatia and Serbia, near Liberland.

A beautiful 19th-century mansion slowly crumbled and became a 'ghost house' after World War II.

The haunting ruins of a military fortress turned astronomical observatory sit on a Sarajevo mountaintop.

A war-torn Olympic relic is being overtaken by graffiti and nature.

The place where World War I began.

A tiny church on a man-made island in the Adriatic.

A mysterious ancient cemetery with Roman sarcophagi and Lycian inscriptions.

A Lycian city of the dead carved into the hillside of Southern Turkey, complete with startlingly human touches.

Roman ruins, natural methane fires and a lovely beach.

Flames have been burning within this mountain for more than 2,500 years.

A little-known caravanserai hidden among farmhouses in the Turkish countryside.

Once described as the "Eagle's Nest," this ruined ancient city rests on a remote mountaintop.

The best-preserved ancient theater in the world.

Naturally protected city carved from a rock face.

While not Turkey's deepest underground city, this subterranean redoubt is the largest.

The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

One of the largest wooden constructions in Europe was meant to be a casino, but soon became an orphanage.

This half-forgotten fortress was constructed by the Ottoman conqueror of Constantinople.

A gorgeous, Gaudí-esque stairway constructed in the city of Istanbul by a prominent Jewish family.

This museum was invented in a novel before being made real by the author.