The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

This fast-food outlet is the only space and UFO-themed McDonalds in the world.

This brightly made over hotel hides decades of suicide, serial killers, and mysterious deaths.

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

Wedding chapel's mysterious spiral staircase said to be miraculously constructed.

This popular pilgrimage site offers a hole filled with holy healing dirt.

This grand stone tower was dedicated to a famed American humorist almost by coincidence.

Paranormal experiences in this hotel's room 217 led Stephen King to write "The Shining."

The prototype for all Nazi concentration camps.

A striking 12th-century-style castle built on the edge of a cliff.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

The fairy tale castle of the "fairy-tale king."

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

The moving metal works of one troubled artist can still be viewed on his front lawn... for now.

The haunted reputation of these abandoned Colorado train tunnels is probably not helped by the terrifying spiked fence.

This super steep hike ascends 2,000 feet in less than a mile.

While most of the games in this arcade take quarters, that would have been a small fortune when they were made.

Even in death, he's still your huckleberry.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

Thanks to a quirk of elevation this gift shop produces magic doughnuts that are found nowhere else on Earth.

Hidden beneath a bridge, this waterfall is known for the large amounts of graffiti painted on its base.

At this Denver landmark, the meals are compulsory, the sopapillas are complimentary, and the insanity is everywhere.

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

Wondrous sandstone hoodoos where Native Americans collected clay for pottery, 9,000 years ago.