Cold war icon and onetime "hole" in the iron curtain.

Hiding the longest subterranean river known in the world.

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

The ruins of this Dutch castle sit atop a labyrinth of once-secret tunnels and passageways, dating back over 900 years.

Standing in a state of "arrested decay," this ghost town allows for a detailed peek into Gold Rush life in an unusually harsh climate.

Brightly colored 30-foot-tall totems light up the desert sky just outside Las Vegas.

The neon signs from Las Vegas' past find their final resting place at this unusual graveyard.

This fairy tale forest hides scenes from some of the more obscure and bizarre Western nursery stories.

A UFO-shaped event building originally intended to be a science museum showcasing the future.