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

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

One man has carved a number of natural New Mexico caves into psychedelic sandstone temples.

On Japan's Tashirojima Island, cats are king.

Crammed inside this grounded passenger plane is a bar that was once a Communist hang out and is now a ratty relic.

The curious and tiny collection contains some very odd objects.

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

A house of bones — but nobody is quite sure to whom they belong.

An outdoor sculpture park of giant pink robots and post-apocalyptic Christmas scenes.

A Buddha-filled cave that is named after a giant monster spider.

Underwater art project will double as a massive artificial coral reef to help regenerate the damaged ecosystem.

An island filled with hundreds of hanging, decomposing, decapitated dolls.

Cretean quarry suggests real-life site for ancient Greek myth of the man-eating Minotaur in his labyrinth.

The quirky - and private - constructions of a secluded artist depict the house of God.

A 16th-century horror show built in a lovely Italian garden.

Gigantic mosaic sculptures of the figures on Tarot cards fill this colorful Tuscan garden.

This 16th-century monastery has been turned into a surrealist architecture compound.

Giant nude woman of Tijuana is also the artist's home.

The original goat tower, the one that started it all.

Architectureal fantasy quarter of Rome.

A Buddhist theme park brings you a Buddhist version of Hell.

A school teacher's massive and terrifying self-built castle.

A Belgian self-built tower inspired by the Bible and ancient civilizations.

A mosaic-tiled house built by graveyard sweeper Raymond Isidore.