An angular maze of concrete in Grand Rapids acts both as public art and as a staircase for fish traveling upstream.

Part of a worldwide art project, this mysterious semicircle of concrete shapes holds the pieces of a larger story.

Covered in tens of thousands of coats of paint, this Indiana attraction holds a world record all its own.

One man's vision and a labor of love of many.

A medical facility that has been kept frozen in time.

A stunning, abandoned limestone quarry in southern Indiana provided the stone to erect the Empire State Building.

The longest navigable underground river in the United States is home to countless blind and albino animals.

Church in Manhattan holds the bloody sock of Padre Pio, among with many other unusual relics.

One kilometer of thick brass rod laid out before your eyes.

The wooden octagon in which Huckleberry Finn and A Connecticut Yankee were born can still be visited in upstate New York.

Dedicated to the art and science of glass in equal measure, this space is as much laboratory as museum.

This once sprawling resort now sits abandoned, filled with graffiti and vibrant colors from an era long passed.

Final resting place of two dozen New York City harbor ships.

Surprisingly aquamarine waters fill deep lakes formed at the end of the last ice age.

Why have you never heard of the second most popular tourist site in New York?

An abandoned 19th century quarry in the middle of the woods, remade by unnamed wanderers into a massive series of rock thrones.

This natural rock "church" might not be a proper chapel but that doesn't mean it's not beautiful.

A winding, cliffside stretch of road overlooking the Delaware River.

A six-story treehouse offers spectacular views of New York's Finger Lakes region.

For over 80 years, Mayan ruins stood proudly in a most unlikely location.

The rustic think-space of famed naturalist John Burroughs stands exactly as he left it.

An unusual sand beach in the middle of a forest.

This museum in the woods evokes the work and lives of Michigan's 19-century lumberjacks.

On this wooded path, a stained-glass window creates a spellbinding forest cathedral.