A mountain range on an active U.S. Navy base hides thousands of mysterious prehistoric rock carvings.

A cablecar-station-turned-revolving restaurant with 360-degree views of the Swiss skyline.

Secret US military film studio in the Hollywood Hills.

A remote candy-striped mountain in the Peruvian Andes straight out of the pages of Dr. Seuss.

It's hard to believe the dizzying patterns covering this abandoned mine are completely natural.

A rare example of World War I trenches from the British front.

The bartenders at this crime-fighting theme cafe are actual private detectives by day.

A deserted hodgepodge of experimental structures designed by nearby university students.

The remote graves mark the mysterious deaths of four 19th century explorers.

The peaceful space is adorned by paintings by the famed abstract artist Mark Rothko.

Where Aleister Crowley attempted to seize the Hermetic Order of the Golden Dawn in a mask and a kilt.

One lonely, modern pyramid has gone from corporate think tank to deserted boondoggle.

This massive geographical sculpture is so subtle, it's possible to pass by it without noticing.

The beauty and the beast of hydraulic mining is on full display at this California Historic State Park.

Fire meets ice at the southernmost volcano on Earth.

The famed architect designed this Minnesota gas station of the future with a lookout tower.

This concrete ship has had four careers - World War I tanker, floating amusement park, fishing pier, and artificial reef.

The decaying remains of a ship whose captain mysteriously disappeared.

Mysterious craters may have been home to an ancient cult.

Built by prisoners of war, the largest small-scale model ever built includes eight miles of tiny streams that now sit abandoned.

This former steel and coal plant is now a neon-lit industrial fantasia.

A small storefront museum explores the history and myth of West Virginia's famous urban legend.

One of the largest ancient geoglyphs in the world is a tall desert god used for predicting the weather.

The last physical evidence of the Lewis and Clark trail is one of their autographs etched into this giant rock.