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

This fantastical waterfall is hidden in a cave located in a cracked cliff.

A beautiful geyser under environmental threat.

The atmospheric road was never meant to be so creepy.

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

Northern Ireland's Brobdingnagian stepping stones.

Famously misunderstood wonder of the ancient world

A massive underwater sinkhole made famous by Jacques Cousteau.

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

The rocks in this arid basin leave trails of movement behind them.

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

On the Oregon coast there is a natural hole that seems to be draining the sea.

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

Rippling sand dunes frozen in the Arizona rock.

The explorer Captain Cook may have named it White Island, but the Maori call it Te Puia o Whakaari – The Dramatic Volcano.

This small group of sand dunes manages to pack in a strange rainbow of colors.

The centuries-old trees lining both sides of this dirt road may become Madagascar's first natural monument.

Fabulous formations, weird and wonderful wildlife.

Hoodoos, naturally eroded land formations, stand 20 feet tall in the Canadian badlands.

Few other hotels can rival the grandeur of the Castle in the Rockies.

A sacred lake composed of over 300 separate pools of highly concentrated minerals.

This expansive bridge in the Canadian wilderness was originally just built for friends.

This deadly little sliver of beach has seen hundreds of whales beach themselves over the years.

Clusters of huge boulders in the Australian Outback.