Iceland's "Smoky Valley" is a beautiful river that is shrouded in a constant cover of steam clouds.

We heard you like volcanoes so we put a volcano in your volcano so you can die for sure...

A small metropolis of Pueblo cave dwellings have been carved right into the hillside of this national monument.

This huge pile of volcanic boulders hides a stunning network of secret grottoes.

This abandoned Soviet circus is slowly being restored to its Communist-era glory.

A spectacular cave and a beguiling lake.

Hidden in a secluded Greek cove is a pristine beach marred only by the rusting smuggler's hulk stranded on its shores.

The world's largest ship graveyard is the product of decades of corruption.

The rusting hulk of a hand-powered, nearly 160-year-old submarine abandoned in 1869 due to the ravages of decompression sickness.

Stunning examples of Russia's 18th-century wooden architecture.

The industrial monstrosity known as Bagger 258 is a colossal mining machine built in the DDR - but now left for dead in a German field.

A quartet of rusting satellite goliaths are all that remain of a communication network that protected Britain from German and Russian air strikes.

The largest drain hole in the world.

This immigrant bridge once spanned the Thames but is now a fixture of an Arizona city.

This natural French spring has been turned into a magical grotto by Roman and medieval constructions.

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

The world's largest military aircraft cemetery.

Beijing's expansive subterranean hiding spot now crumbles away as a tourist destination.

A mysterious drive-in nestled in the forest that leaves little to the imagination.

Medieval town turned hippie commune, once home to the secret foreskin of Jesus Christ.

A hyper-luxurious, 12,000- square foot home might be buried beneath Queens, still waiting to protect you from nuclear missiles.

A beautiful deserted greenhouse in the middle of a park.

Central Europe's largest collection of mini-bottles is on display at this museum devoted to a bitter Hungarian liquor.

This Victorian-era public house has set the standard for pub-style elegance for over a hundred years.