A 300-yard long natural tunnel runs through a ridge deep in the Appalachian Mountains.

Big gun installations, built over a massive cemetery, now abandoned & hidden in trees.

Storyville was New Orleans' historic red light district and hotbed of jazz music, sometimes referred to simply as "The District."

An extraordinary mixture of natural beauty and man-made phenomena.

Once the tallest building in the world and the site of "the highest dinner ever held in New York" this building now holds the most expensive penthouse in the city.

Nondescript elevator doors open to reveal a stunning, surreal world.

One man's ambition created this psychedelic log home.

Hidden in plain sight on a pair of Manhattan subway tunnels are a pair of public instruments that sing to each other.

A castle built by an eccentric medieval enthusiast in rural Ohio.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

Great place to have a drink and a bite to eat in an atmosphere laden with New York's Bohemian past.

This "zoo" is a cross between a junkyard and a sculpture garden, featuring animals you won't see anywhere else.

The "world's biggest dinosaur" once housed a creationist museum in its abdomen.

This grand mansion has starred in everything from Bones to Buffy.

Read between the lines of the subway map to find the hidden abandoned Civil War fort.

One of the last Jazz Age "Wonder Theaters" in New York City.

The ghost town that ended up on Ebay.

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

A little piece of the Shire is hidden behind a plant nursery in Port Orchard, Washington.

Experience a quartz crystal sound bath inside a storied, all-wood sound-chamber.

This former Norwegian sailor's church is slowly being taken over by ramshackle robot musicians.

The mysterious wonder of an underground waterfall is illuminated by multicolored lights.

An homage to everyone's favorite prehistoric cartoon family.