A clear blue swimming hole with hidden caves, still unexplored.

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

Seemingly grown on some other world, these New Mexico rock formations look like a disused science fiction set.

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

One man has carved a number of natural New Mexico caves into psychedelic sandstone temples.

European castle ruins in an American state park are actually the product of death and grief.

The maximum security facility was once thought to have "the bloodiest 47 acres in America."

Just outside the Ohio Supreme Court sits a testament to justice.

Known locally as "the giant head," this 14-foot LED sculpture has a photo booth in the neck where you can have a 3D picture taken and displayed.

A county library in rural Ohio houses one of the finest mineral collections in the world.

A gregarious Ohio resident has been building his whimsical temple to peace for decades.

Medical history museum featuring a lovely doctor's office from the 1800s.

A history of tragedy and a pile of eerie stories have contributed to this house's consistent ranking as one of the most haunted places in Ohio.

These sub-farmland caves are home to a majestic stalactite known as the "Crystal King."

This collection of Japanese luck idols beckons visitors with over 2,000 waving paws.

The only remnant of a small mining town is an abandoned railroad tunnel that is steeped in ghostly lore.

The entrance to this sinisterly named tunnel hides behind a Tim Hortons.

Faces carved into the cliffs create an otherworldly walking trail.

The largest earthwork effigy in the world.

A collection of Witchcraft artifacts and occult paraphernalia started by the leader of the Long Island Coven.

Where beautiful signs live on forever.

This magnificent Cincinnati graveyard is also a popular public park.

Take a drunken tour inside the world's largest known geode.

A bronze of the man in all his sinewy glory celebrates his longtime connection to the Ohio city.