The first declared National Monument in the United States.

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

This abandoned subway station beneath the Waldorf-Astoria hotel is allegedly used to secretly transport presidents.

Monasteries on rock pillars, once accessible only by frayed ropes.

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

Stepping away from the glitz of mobsters and casinos to learn about the other history of Vegas.

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

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

A spectacular cave and a beguiling lake.

The sound of swaying stalks in this stunning grove has been named a governmentally recognized sound.

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

The seamy, underground secrets of Portland's criminal past.

Towering basalt columns, a creation of fire and ice.

The real life Hobbiton, this sheep farm has been forever transformed since being built for The Hobbit film series.

Dodge prohibitionists and slide through the telephone booth in Crif Dogs.

A 16th-century horror show built in a lovely Italian garden.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

A massive underwater sinkhole made famous by Jacques Cousteau.

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

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.

A fiery crater has been burning in the Karakum Desert since 1971.

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

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.