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

These enduring murals depicting a distinctly Marxist tribute to capitalism could not even be defeated by McCarthyism.

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

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

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

The city of Rockford, Illinois is symbolically protected by a quartet of fittingly stony sentinels.

Home to over 300 antique cars and motorcycles, including Thomas Edison's Model A.

A quaint miniatures museum that turns its focus towards the lives of Americans in a simpler time.

Devotional offerings and pleas for intercession are left at this Depression-era shrine inside a nature preserve.

This Renaissance palace features a unique architectural design and is now home to the Ferrara National Art Gallery.