Ruins of a German Castle on top of a towering stone pillar.

A giant Troll lurks under one of Seattle's oldest bridges.

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

Wondrous sandstone hoodoos where Native Americans collected clay for pottery, 9,000 years ago.

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

A submerged archeological park still holds the wonders of a Roman Sodom.

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

France's national museum of scientific and industrial instruments.

A mechanized clock where a man fights off a dragon, crab, and rooster.

A museum of carnival attractions where you are invited to ride the rides.

Abandoned railway line circling the city of Paris.

This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

This historic franken-chapel is the oldest wooden church in the world, at least part of it.

An English artist has turned an unassuming ex-council house into a time-lost house of mystery.

Northern Ireland's Brobdingnagian stepping stones.

Mysterious rocks that ring musically when struck.

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

The world's only museum devoted to the wonders of fluorescence.

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

An eerie, derelict amusement park in Berlin.

A massive underwater sinkhole made famous by Jacques Cousteau.

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

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

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