The superstar of Cold War nuclear bunkers has been featured in countless films but is now barely operational.

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

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

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

Hidden behind musical flora and forgotten for over a thousand years, this cave is now a neon dream.

The lowest point in North America is home to an undrinkable pool surrounded by fields of geometric salt flats.

The first artificial white water river course in North America cuts right through an Indiana city.

This tiny New Jersey village has lived many lives but seems determined to remain a ghost town.

When you visit his grave, be sure to rub the Great Emancipator's nose for good luck.

Isolated atop this Balinese sea crag is a lovely Hindu temple that is said to be guarded by sea snakes.

An isolated dive site teeming with cnidarians.

The "mysteries" of this quintessential roadside oddity were almost destroyed by neglect but were saved by fans of kitschy wonder.

This massive airship factory is so large that it has its own indoor weather.

Once the largest windmill outside of Holland, with enormous 114 foot sails.

Remnants of a storybook amusement park hidden behind a strip mall.

Böttcherstraße's bells, extolling Nordic virtues and the great conquerors of the world.

Law-protected wreckage serves as a peculiar memorial for an almost forgotten World War II tragedy.

Visitors can walk over the largest concentration of Columbian mammoths to have died from one event.

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

The rusting remains of the largest assembled WWII fleet on the West Coast.

This historical theme park celebrates all things noodle.

An artsy hidden staircase leads to breathtaking views of San Francisco.

Devilish landscape, once cinema home to giant alien bugs, now derelict roadside attraction.

Beautiful carved tunnels.