Odd outsider art installations surround a Gold Rush-era ghost town.

Enormous lake at the bottom of a unique cave system.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

A spectacular cave and a beguiling lake.

An isolated dive site teeming with cnidarians.

A hand-built folk art installation covered with messages of God's love.

The ghostly remains of an accidental sea.

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

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

Stunning wetlands ablaze with pink lotus flowers.

A trash dump made beautiful by nature's power.

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

The old Niles Canyon Aqueduct in the San Francisco Bay Area is a bemusing and secret trail through nature for wayward travelers.

Dramatic river bend surrounds a natural red-rocked pedestal.

A swing to dangle you off the very edge.

Mother Nature outdoes herself with this stunningly beautiful set of caves carved into marble.

A massive underwater sinkhole made famous by Jacques Cousteau.

An eerie, derelict amusement park in Berlin.

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

Medicinal spa created with the discharge from a geothermal energy plant.

A bizarre house filled with an astounding array of collections.

An artsy hidden staircase leads to breathtaking views of San Francisco.

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

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