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

Homemade outdoor church and sculpture garden decorated with glass shards.

A tiled, multi-level garden of survival in Lyon.

Naturally protected city carved from a rock face.

Live-in sculpture begun by one family in 1979.

A whimsical garden of outsider art in the Spanish countryside.

Famed architect Antoni Gaudi built this generous thank you gift to a friendly host who housed him during a job.

An underground city of salt.

A quirky house created entirely out of glass bottles combines a collector's spirit with an artist's flair.

A Spanish artist builds his own castle.

A Boeing mechanic and his wife leave a whimsical, stone sculptured garden as their legacy.

Hanging over one of Japan's "hidden valleys," these vine bridges must be remade every three years.

Rainbow-hued local gem in Venice.