A museum befitting the city responsible for supplying the majority of the world's LSD.

A spectacular rainbow of stained glass makes the "Pink Mosque" one of the most beautiful in Iran.

Even Henry David Thoreau found this glacial pothole irresistible.

This massive subterranean fissure is known as the "underground Grand Canyon."

A Jenga-style cylindrical tower of books that appears to go on forever.

One of the few surviving examples of the first lock and dam system built on the Ohio River.

One Confederate statue that accurately reflects the ugliness of its subject.

Rebuilt several decades ago, its striking murals prevent it from being reconsecrated as a church.

British troops and Prohibition couldn’t stop this spot from becoming one of the United States' oldest continuously-run taverns.

The development of this cliffside waterpark is representative of Mexico's history of co-op tourism developments.

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

The only swimming pool listed on the National Register of Historic Places is emptied and refilled each day with naturally filtered water.

An abandoned railroad tunnel is now filled with bioluminescent bugs.

This icon of the Atomic Age now lays dormant.

A "miracle" that seems to produce more holy fistfights than holy revelations.

Also known as "Robin Hood's tree," this tree became a famed location along Hadrian's Wall before it was cut down in an act of vandalism.

More than a century after her death, Little Gracie Watson remains one of Savannah's most often-visited residents.

A nearly 500-year-old sculpture depicts a man eating a sack of babies, and no one is sure why.

An unusual art exhibition in a suburban yard is designed to awaken the souls of those flowing by.

A technicolor place of worship for Elevationists.

An architect transformed this abandoned cement factory into his castle-like workshop.

The world's largest squirrel statue clutches a pecan bigger than your head.

It's not a typo, now say it five times fast!

A room in New York City that contains 250 cubic yards of dirt worth a million dollars.