This national park dedicated to the tallgrass prairie ecosystem still displays its military past.

An exhibit of items from the mental institution where Mary Todd Lincoln lived after her son conspired to have her committed.

This house renovated by Frank Lloyd Wright was the centerpiece of a lavish 20th-century estate.

Known as the "Cross At The Crossroads," this massive metal cross is just short enough to avoid the FAA.

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

This monolithic statue was erected in honor of Chief Black Hawk (even if it wasn't made to look like him).

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

The original vault that held the president's remains still stands, empty, not far from where he was finally buried.

The clothes-washing king doubles as a community center with some unusual features, including an aviary filled with finches.

This historic Illinois "Muffler Man" has been converted from axe-touting lumberjack to rocket-wielding space ace.

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

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

One of the few remaining relics of the meatpacking hub that made Chicago the "hog butcher to the world."

Roses and other fascinating flora fill this garden built to commemorate Britain's immortal Bard.

A hidden grotto on the grounds of the Kane County Government Center.

A historic beacon built in the aftermath of the worst maritime disaster on the Great Lakes.

This cemetery is all that remains of a school for "wayward" girls.

In the Shawnee National Forest, amazing rock formations peer through the treeline.

While he no longer has an eatery to give him context, this off-brand Paul Bunyan still holds his giant hot dog with pride.

This bronze sculpture on a former squash court marks the secret origins of the Atomic Age.

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

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

Arguably the best example of an authentic Dutch windmill in the United States, rivaling its counterparts in the Netherlands.

Tour the luxe "glass cage" that inspired and unnerved the architecture world upon its debut.