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

One of the largest, oldest, darkest, quietest motel rooms in the world.

The first declared National Monument in the United States.

One of the world's largest model railroads is a mind-boggling achievement.

This rugged area of red rocks and arches is often considered one of the most beautiful places on Earth.

A self-built castle made by a mysterious man.

Rippling sand dunes frozen in the Arizona rock.

A spiritual vortex among the red rocks in Sedona.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

Three wildly colorful calderas top this otherworldly volcano chain.

This conservatory allows a little bit of the tropics to thrive in the middle of a major Canadian city.

New Orleans' famous cemetery, located on the site of a former race track.

A sprawling nature preserve harbors the world's only living dragons.

A New Zealand communications tower stands as the tallest structure in the Southern Hemisphere.

Mysterious stone tower featured in many alternative histories of the New World.

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

The Hudson River School comes alive at this palatial estate.

Island where motor vehicles are banned -- home to the only carless highway in the United States.

This "thrice-cursed" island is allegedly home to Captain Kidd's lost treasure.

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

A castle built for love, and abandoned due to heartbreak.

A centuries-old lookout post still sits atop a natural stone spire.

This spa theme park lets its guests take a dip in pools of coffee, wine, or ramen broth.

This giant meditative chakra sits peacefully in the Flathead Valley of western Montana.