This former tuberculosis research hospital endeavored to cure the dreaded disease with fresh air and positive attitudes.

The world's longest known cave system.

Once known as the Illinois Asylum for the Incurable Insane.

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

Once an ornate movie theater remade by Catholic Charities.

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

This architectural stunner is one of the few surviving Egyptian Revival theaters in the U.S.

You have to love a museum with a truly dedicated focus. A focus on Superman, for example.

One of the last functioning antique elevators in Chicago.

The 30,000-volume library is one of the world's most impressive poetry collections.

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

The subtle science of a master molecular gastronomist.

This whimsical Oz-themed park had a wonderful impact on the surrounding neighborhood.

At the top of the hour, this steam-powered clock's eight brass whistles play "Back Home Again in Indiana."

Modeled after the labyrinth in Chartres Cathedral, this small-town Indiana memorial labyrinth sits half a world away.

Ornate limestone building now filled with geologic specimens, and more.