A lush green oasis in the middle of Chicago.

This unauthorized stone mermaid was secretly carved out of public stone before being permanently preserved.

These abandoned grain silos and tunnels are an urban exploration dream.

This historic hotel invented the chocolate brownie.

Chicago's museum dedicated to the history of bondage and fetishism is more textbook than titillation.

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

Hot Doug's "Hot Dog" Stand.

What was once one of the country's largest confectionary plants is now an abandoned ruin, but is still pretty sweet.

A Museum of Holography frozen in 1974.

A century-old network of freight tunnels underneath the city's historic business district.

Parking lot where a Chicago mayor was inaugurated under very sketchy circumstances.

Location of the Real World's disastrous, and protested, eleventh season.

A spectacular remnant of an Adler and Sullivan masterpiece that was destroyed in 1972.

A strange rock in Chicago marks the spot where a tree once stood in honor of the 18th President.

A Chicago Movie Palace Lost to Time.

The original Garfield station is the oldest station facility on the "L", with the station house dating from 1892.

Once at the center of U.S. finance, the historic Trading Room was meticulously recreated piece by piece and rebuilt in the Art Institute.

Theater has had many different incarnations but has survived the ravages of time.

A 400-foot-tall tall map of Chicago makes this once-ignored building stand out.

This memorial plaque remembers a strangely shallow maritime disaster known as "Chicago's Titanic."

Illegal drag racing two stories beneath Chicago’s streets.

An eccentric park and pool.

No one knows how many bodies are in this vault in a Chicago public park.

To find the "unicorns of the deep" you've got to go downstairs.