Not merely a museum – but a whirring powerhouse that offers a subterranean peek into the heart and soul of cable car operations.

San Francisco's urban bison herd has persisted in the face of extinction, development, and disease.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

This upscale streetwear store is hidden behind a fake Snapple machine in the back of a deli.

This abandoned Slovenian military barracks has become a punky-political art squat.

A whimsical bridge adorned with decorative dragons.

This one-time health resort was used by aristocrats around the world.

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

This mysterious but iconic tapered tower appears in many Azeri fairytales and legends.

Mysterious hillside with a continuously burning natural fire.

The fire inside this temple has burned for more than 1,500 years.

A dreamy mausoleum honors Persia's most famous poet.

This ancient burial site is believed to be one of the first earthquake-protected structures in the world.

17th century mosque for Shah Abbas' harem.

The ancient necropolis houses the immense rock-cut tombs of four Persian kings.

Putrefaction plateaus in Iran, where the dead were sent for decontamination before going to their final resting place.

A spectacular rainbow of stained glass makes the "Pink Mosque" one of the most beautiful in Iran.

The palace of the King of Kings, burned by Alexander the Great.

Mirrors and glass shards cover every inch of this arrestingly beautiful mosque.

The world’s largest digital waste dump has become a site where organized criminals hack into confidential government data.

This series of rope-style bridges brings visitors into a jungle layer that is usually reserved for birds and monkeys.

The souls of the dead have made these Ghanese crocodiles shockingly docile.

Where thousands of slaves passed through the "Door of No Return."

At Ghana's largest wildlife refuge you feel like you're right in the animals' backyard.