The seamy, underground secrets of Portland's criminal past.

These old stone ruins in the Oregon wilderness were once bathrooms and are steeped in legends of murder.

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

Nature's biggest mammal swims in landlocked Oklahoma.

An immersive art experience built by local arts collaborative, Factory Obscura, in the building formerly known as The Womb, a psychedelic arts center founded by the frontman of the Flaming Lips.

Final resting place of Geronimo, Quanah Parker, and the first atomic gun ever fired.

Dad jokes and wordplay abound in this comic fake cemetery.

Collection of skeletal systems from the "world's leading supplier of osteological specimens."

Tucked away on an empty wooded lot in suburban Oklahoma City lie the remnants of an abandoned circus camp.

A whimsical tower with a spiral staircase, inspired by the Space Age and the Möbius strip.

An acoustic anomaly with a mysterious cause.

The site of a tragic massacre that spawned a multimedia franchise.

An unrealized dream to wirelessly electrify the entire Earth.

The second-largest (of only two in the world) large particle collider is the underdog of experimental physics.

Beneath the mossy overgrowth covering this once-sprawling campus lies decades of history and the secrets that come with it.

A formerly abandoned mental institute, now back in business.

An enormous cat made of recycled wood scraps.

The abandoned ruins of America's first private zoo are open for exploration in the Catskills.

A Gothic-style abode built to accommodate the church's three resident peacocks.

The phone booths of New York City have all but disappeared, but their remains were once found in this "graveyard," sadly now removed as well.

These small stands sell Malian snacks to worshippers and passersby after Friday prayers in Harlem.

Harlem park dedicated to compulsive hoarders killed by their own junk.

A memorial marks the library lobby where Langston Hughes' ashes are buried.

This speakeasy continues the Prohibition-era legacy of Harlem's jazzy Swing Street.