One woman's UFO-themed campground, complete with self-built energy vortexes, UFO-themed weddings, and magic bushes.

The largest self-built castle in the U.S., six decades in the making.

This naturally-sourced hot spring is now home to a clothing-optional resort.

Crystal clear lake with a shoreline of travertine located in a Colorado canyon.

These curious caverns have been home to mushrooms, gangsters, and disco.

Half of a waterfall goes into the river while the other half seems to disappear.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

This small primate research island is teeming with playing, fighting wild monkeys.

The rocks in this arid basin leave trails of movement behind them.

This dramatic sea spire is home to the world's rarest insect and is part of the lost continent of Zealandia.

The first North American landing spot for James Cook on his third voyage of discovery in the Pacific.

100-year-old shipwreck you can walk up to at low tide.

Where Nor'easters go to die.

The longest continuous lava tube in the continental U.S. offers 2.5 miles of dark explorations for the adventurous.

Two massive rock outcroppings on the Oregon coastline.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

Beyond being incredibly fun, not much can be said about the Hole with certitude.

Tens of thousands of tiny birds swarm into one school chimney every fall.

A monument in a town outside of Boston celebrates the visits of Edgar Allan Poe.

The railroad tunnel nicknamed the "Bloody Pit" for taking the lives of hundreds during its construction.

Collapsing castle on the Hudson river was once the storage site of military surplus business.

The legend of a local monster still haunts this small town.

A mysterious drive-in nestled in the forest that leaves little to the imagination.

One man's homage to the orange as realized through a long-term folk art labor of love.