This museum started as a collection of Manhattan Projects and continues to add exhibits as they are declassified.

A unique geological area spiked with wind-carved rocks that resemble teepees.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

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

An artificial crater field that trained astronauts for lunar exploration.

A lighthouse built to save lives that took quite a few with its treacherous location.

Two mammoth statues inspired by equally tall tales lure tourists to this roadside attraction.

Nestled in the heart of San Francisco’s bustling Financial District stands a unique homage to the Mayan and Beaux Arts.

Quite simply the largest tree in the world (by volume).

San Francisco's newly reopened hands-on science museum.

A walk-in working camera obscura produces 360-degree live images of the San Francisco coast.

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.

A winding path built in secret on the edge of the continent.

This shop specializes in oddities and Victorian-inspired wonders.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

A beautiful 62-acre Catholic shrine and botanical garden.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

A slightly creepy gallery of plaster cast models in the same museum as Michelangelo's David.

William Faulkner kept his beloved estate wild and untamed.

Giant novelty guitars now mark the spot where Robert Johnson is said to have sold his soul to the devil.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

A once-booming Mississippi River town with a history of racial violence is now eerie and mostly abandoned.

The bad-ass ride of a soul legend, housed in one of the world's few soul museums.

When Motown musicians came to Nashville in the 1960s they stayed at this historic record-pressing company because hotels wouldn't host them.