Erosion and time have created a naturally-formed water park.

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

This pair of eccentric Ohio castles were built by a pair of brothers who wanted to bring a bit of class to the Ohio wilderness.

A castle built by an eccentric medieval enthusiast in rural Ohio.

This modern castle sat empty for decades before a fire inspired its builders to complete its luxury halls.

This Mediterranean castle was built for a millionaire and his giant dog.

What's left of the ruins of the 1893 Columbian Exhibition, or World's Fair, also known as the White City.

Arguably the best example of an authentic Dutch windmill in the United States, rivaling its counterparts in the Netherlands.

What may be America's largest classic video game arcade lurks inconspicuously in a Chicago suburb.

A turn-of-the-century architectural marvel built on healing mineral springs and salt licks.

Symbolic attempt to overcome the issues of life.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

Fresh wooden posts have been added to ancient holes to recreate a primitive henge clock.

This freshwater spring fills with 10,000 gallons of water per minute.

Legs Inn provides Polish food, a cornucopia of Native American artwork, wood carvings, and mounted deer heads.

Strange physical sensations and optical contradictions keep visitors coming back for more.

Museum dedicated to the art of cutting and polishing stones.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

This museum celebrating the almighty dollar lets visitors literally stand in the shadow of a million bucks.

An antiquated German apothecary on Chicago's North Side.

A rural hall of justice holds the world's only comic book and superhero museum.

Home to the world's largest refracting telescope and the birthplace of modern astrophysics.

A place to eat for on-the-run agents and espionage enthusiasts.

Annual convention held by the largest pyrotechnic community in the world.