The most visited, and possibly most controversial, museum in Germany.

Visitors can explore the role of mysticism throughout the ages inside this interactive museum of magic.

This impressive chasm is one of the longest natural underground cavities in the world.

One man's desire to transcend art led to the construction of this outsider chapel.

One of the largest ochre quarries in the world, hidden in a limestone landscape.

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

The castle was reconstructed to fit Kaiser Wilhelm II's romanticized vision of the Middle Ages.

A crumbling island fortress that seems to be covered in a field of stone crosses but is simply incomplete.

The remains of this castle, known as the Witch’s Eye, watch over the Thur Valley.

This collection of French root art looks like an indoor fairy wonderland.

An abandoned beach resort in Normandy reclaimed by artists.

This professional clown's home is an outsider art wonderland.

Exquisite wall sculptures carved in secret by an early quarryman in an obscure corner of the Paris Catacombs.

An enchanting work of outsider art, full of whimsical sculptures and carvings.

Tens of thousands of ancient rock carvings hidden in the heart of a French national park.

The beautiful bas-relief lines a sliver of a 19th-century walking path between two charming French villages.

A chapel on a volcanic core, marking the end of a successful journey.