This palatial botanical garden is home to one of the largest pipe organs ever installed in a private residence, and a piece of Wood's cycad.

These tourist trap caverns are said to be the former home of a legendary Pennsylvania Hermit.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

World's first "penitentiary," meant to be humane, drove men insane.

Massive puppet-automaton machines created by French artist collective Machines de l’Ile.

One of the most powerful religious centers in the Middle Ages, dubbed the founder of Western monasticism.

Do these monsters look familiar? The gargoyles on this church are all from pop culture.

Two small chapels housed inside an ancient tree.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

Baroque celebration of the end of the Great Plague of Vienna.

Legends surround an ancient tree trunk riddled with nails for good luck.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

The world's most elegant power lines.

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

Lyon, France is home to two remarkably preserved Roman theaters, one dating back to 15 BCE.

Hundreds of hidden passageways weave through the old quarters of Lyon.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

The final resting place of the great navigator, or maybe his brother.

The world's largest wooden structure.

For hundreds of years, automatons moving to metallic music have been marking the passage of time.

A colorful piece of contemporary art cheerfully clashes with Lyon's historical architecture.