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

Recognized the world over as the home of the McCallisters in the 1990 movie "Home Alone."

An outdoor urban gallery of large-scale artworks by the world's most influential street artists.

A science teacher's dream.

This alley in downtown Chicago held the bodies of over 600 people after the fateful Iroquois Theatre fire.

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

All of Chicago's wood-paved streets are long gone but two alleys remain.

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

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

Chicago's largest cemetery is full of beautiful Victorian monuments and more than a few ghost stories.

A once-booming Mississippi River town with a history of racial violence is now eerie and mostly abandoned.

An enormous park-like oasis, full of famous Chicagoans’ graves.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

A lush green oasis in the middle of Chicago.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

Hot Doug's "Hot Dog" Stand.

Despite its name, this fast food museum is actually a replica of the ninth McDonald's store.

A onetime gangsters' hideaway where you can dine on steaks, fine wines, and cigars just like they once did.

Hidden on the seventh floor of a historic building, this Cajun spot features wall-to-wall bottles of hot sauce.

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

A hot dog stand where the heads are just as hot as the dogs.

A notorious Route 66 eatery once frequented by Al Capone.

This historic hotel invented the chocolate brownie.

The only cave in Louisiana has played host to a state's-worth of clandestine activities.