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

The absurd creation is a compulsory destination for selfies in Buffalo.

A room hidden behind a swinging shelf in the children's section.

The ruins of the suspension bridge hang over Kingsbury Run as a ghost of racial prejudice.

World's first "penitentiary," meant to be humane, drove men insane.

What was once the second largest steel mill in the US is now a sprawling complex of modern ruins.

Abandoned concert venue legendary for its rock counterculture.

This public space is speckled with the eerie remnants of a defunct amusement park.

This last stalwart of the now-forgotten feminist restaurant movement has been serving food in an activist atmosphere since 1977.

Detroit housing collective working to create an "environment for revolutionary change."

A castle that was built stone by stone by an eccentric journalist.

Hand-crafted tributes to a stray cat named "Room 8" now cover this LA elementary school.

Once the central jail for Los Angeles, this building housed inmates like Al Capone, those arrested from the Zoot Suit and Watts Riots, and individuals imprisoned for their sexuality.

Historic house-museum dedicated to the revolutionary gay graphic artist Tom of Finland.

A rough granite monument marks the spot where Europeans first caught sight of the San Francisco Bay.

This restaurant features Native American foods from across the country.

San Francisco's oldest surviving monument and meeting place for 1906 survivors.

This giant head is all that remains of a once proud statue that survived an earthquake but not a fall off of a wagon.

Bible stories are brought to life with gloriously cartoonish kitsch in this South American theme park.

105-foot wide giant metallic flower blooms anew every day in the heart of Buenos Aires.

This historic, palatial theater is now one of the world’s most beautiful bookstores.

A tiny museum housed in a New York freight elevator specializes in the "overlooked, dismissed, or ignored."

The competition: breathe deeply as long as you can.

A young woman's senseless murder led to the controversial psychological theory of the "bystander effect."