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

A stunning landscape of bunkers that once stored chemical weapons.

Despite a history of destruction, this former citadel survives to document Afghanistan's oft overlooked history.

A sturdy relic of Britain's once crucial gunpowder industry is now a haunting Cornish ruin.

A Singapore shrine to an unnamed German girl who has become a local deity.

The original film set of Luke Skywalker's Tatooine home from the 'Star Wars' trilogy.

The ship that got left behind.

The world's largest ship graveyard is the product of decades of corruption.

An enormous, 30-story-deep hole in the middle of Guatemala City.

The Voodoo Superstore of the world.

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

The rusting remains of the largest assembled WWII fleet on the West Coast.