For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

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

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

The most alien-looking place on Earth.

A trash dump made beautiful by nature's power.

A natural gas leak provides a flickering flame beneath a waterfall.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

Staves, storm-calling, and of course, necropants.

An Australian lake whose pink hue defies scientific explanation.

Towering basalt columns, a creation of fire and ice.

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

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

Hot springs monkey spa in the middle of Hell's Valley.

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

A seemingly endless landscape of pure salt stretches far across Bolivia.

Dramatic river bend surrounds a natural red-rocked pedestal.

The fairy tale castle of the "fairy-tale king."

An isolated dive site teeming with cnidarians.

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

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

A massive underwater sinkhole made famous by Jacques Cousteau.

Most-visited and most-photographed slot canyon in the American Southwest.

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