Treehouse motel and treehouse-building school.

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

An underwater restaurant, surrounded by a coral reef.

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

A breathtaking bridge that crosses a vast gorge over a river's torrents, and has a tale of a devil architect attached.

Huge stone depressions which may have acted as an Incan agricultural experiment.

An ancient church on a tiny island covered in stone bible stories has controversially been turned into a museum.

This trio of Australian rock spires may have inspired aboriginal legend or just modern tourism.

A Netherlands hotel where you can sleep inside a wine barrel.

Clusters of huge boulders in the Australian Outback.

Hundreds of tiny dead butterfly eyes gaze down at diners in this Australian eatery.

This $62 million dollar temple was erected to house one little dental fragment of religious history.

A palatial sculpture park was built illegally and in secret by a self-taught artist over 36 years.

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

These tombs were built into the side of a mountain so that ancient angels could reach the dead.

The fairy tale castle of the "fairy-tale king."

An ancient rock engraving shows Aboriginals used their advanced knowledge of the stars to hunt and gather.

The artist James Turrell is repurposing an extinct volcano crater as an observatory to experience the cosmos.

Pilgrimage site for star-crossed lovers.

A lovers' beach, tucked below the surface of the island, provides a safe haven for romance.

This small town in the Netherlands has no roads but instead, miles of canals and over 100 bridges.