A little-known subterranean street runs under some of the best-known buildings in Chicago's River North.

Illegal drag racing two stories beneath Chicago’s streets.

A shining sculpture made of 3,115 lights, the number of visible stars in the Northern Hemisphere.

Fragments of architectural wonders from around the globe are embedded in the newspaper building's walls.

The iconic Chicago sculpture hides a beautiful and easily overlooked plaque on the backside.

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

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

Each of these gorgeous, intricately decorated rooms is painstakingly crafted to the scale of 1 inch: 1 foot.

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

The last remaining vestige of a popular 1999 public art display.

The last masonry skyscraper ever built reveals a transitional moment in architectural history.

This abstract sculpture is rumored to cast a hammer-and-sickle shadow once a year.

This surprising gem is a world-class archeological museum hidden at the University of Chicago.

This modest post office sits on the site of H.H. Holmes' famous murder castle.

From banquet hall to Masonic Lodge and now concert venue, Ganz Hall is a breathtaking glimpse of into the golden age of American architecture.

In 2004, a Dave Matthews Band tour bus dumped 800 pounds of waste off a bridge and onto an unsuspecting tour boat below.

The twin towers in this Chicago fountain use 50 foot tall video screens to spit on people.

A journey begins with a single step, and for many, the road-trip of a lifetime started at this Chicago intersection.

This steep slide at a kids’ playground went viral after an police officer tumbled down it.

A mysterious stone embedded at the base of a historic Boston building.

This nearly 200-year-old restaurant's history includes an exiled French prince, JFK, and a very hungry Daniel Webster.

This plaque is dedicated to a historic hotel’s Canine Ambassador and the subject of two children’s books.

A pair of antique trolleys are on display at one of the oldest subway stations in the United States.

These structures serve as a memorial to one of Boston’s most ambitious and controversial urban redevelopment projects.