This shallow cave got its name from copious amount of human bones found inside.

The only surviving prototype for Buckminster Fuller's house of the future.

A Beaux-Arts triumph set to become Ford's innovation campus

A popular place to pick up prehistoric coral fossils from the time when Michigan was an ocean.

Island where motor vehicles are banned -- home to the only carless highway in the United States.

Largest magic museum in the United States with more than half a million pieces of memorabilia.

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

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

Hell on Earth is actually a small town in Michigan where anyone can be mayor for a day.

Abandoned concert venue legendary for its rock counterculture.

The face of the famed flier in a hillside in her hometown.

This lesser-known geographic marker was the reference point for all surveys of the continent for 75 years.

This is not your typical jungle gym.

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

The man who was president for only one day and spent most of it asleep.

A plaque on the side of a parking garage marks the burial place of a great Ottawa chief.

A peculiar forest that was handcrafted for government experiments.

Claims to be the "World's Highest Hill."

This three-dimensional brick mural is the longest of its kind in the United States.

A statue high in a hill that represents how Buffalo Bill got his name.

One of the Eight Wonders of Kansas and the first official National Natural Monument these stark formations look like nature's Stonehenge.

A town pays homage to its namesake.

This century-old roadside attraction is full of bizarre rock formations.

This futuristically sylvan church is a glass-enclosed marvel of modern architecture.