Walk 2,300 feet above the ground on the "Troll's Tongue."

Surreal riveted sea forts once protected the Kent shores from German attack.

Breathtakingly blue walls shimmer inside the "Glacier Behind the Town."

Natural time capsule containing an alien ecosystem.

A beautiful geyser under environmental threat.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

An ethereal glowing blue ocean cave in Croatia.

A gargantuan crystal kingdom.

The atmospheric road was never meant to be so creepy.

An Aztec snake god has taken the material form of an apartment complex.

One man has carved a number of natural New Mexico caves into psychedelic sandstone temples.

A serpentine highway twists and turns over the treacherous Norwegian Sea.

Thousands of exquisitely carved stone water storage wells, hundreds of stone steps fill this exquisite medieval stepwell.

Northern Ireland's Brobdingnagian stepping stones.

The world's highest and most dangerous infinity pool lies at the precipice of Victoria Falls.

An enormous, inside-out glass globe built in 1935.

Stunning wetlands ablaze with pink lotus flowers.

Dramatic river bend surrounds a natural red-rocked pedestal.

An ancient capital city that dates back 3,000 years old and harbors many surprises.

An exquisite tunnel of cascading flowers.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

Rippling sand dunes frozen in the Arizona rock.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

This one-of-a-kind archeological site is home to strange prehistoric ruins, the original use of which is still a mystery.