Largest collection of mounted dinosaur specimens in the world.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

Dig for your own trilobites in this goldmine of invertebrates.

This geothermal hot spring hides beneath a slowly growing mineral dome.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

One of the world's oldest and most massive living organisms is a grove of quaking aspens.

Bringing back the art of handmade custom coffins.

The smallest country in the world.

An eatery for UFO seekers on the Extraterrestrial Highway.

This incredible collection of vintage pinball machines can be played at 25 cents a pop.

Strange beasts lurking in a garden are all that remain of a quirky, short-lived theme park.

Most-visited and most-photographed slot canyon in the American Southwest.

A 35-foot-tall fork stuck in the ground outside an office building in Missouri.

Like Stonehenge, but with boats and oodles more charm.

This is not your typical jungle gym.

The show pony of cave systems, Fantastic Caverns manages to live up to its name.

The "World's Largest Underground Business Complex," a 55,000,000-square-foot city underneath Missouri.

A historic house in St. Louis was plagued by a series of suicides committed by family members involved in a successful brewery.

A late sculptor's last project was to turn this abandoned cement factory into a castle-themed amusement park.

An unexpected but incredible collection of wildlife dioramas spanning rainforests, swamps, forests, and plains.

A chessmaster's dream destination.

Entombed in this strange, white stone hill are the deadly remains of radioactive weapons production.

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

A creepy sculpture of a decapitated head invites viewers to see St. Louis through its empty eyes.