A plaque marks a former safe house on the secret route, now hidden next to a McDonald's.

This abandoned 19th century orphanage started as a boarding school for children of Civil War veterans.

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

Cold War missile launch site which has been converted to a public park.

This botanical garden outside Chicago boasts an array of more than 300 varieties of lilacs.

In the loving memory of a tragically deceased role-player this Illinois park is decked out with both dungeons and dragons.

Quirky water tower advertises the long-gone Brooks Tomato Products Co.

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

A notorious Route 66 eatery once frequented by Al Capone.

A replica viking ship from the Chicago World's Fair is still in dry dock in an Illinois park.

The city of Rockford, Illinois is symbolically protected by a quartet of fittingly stony sentinels.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

These pretty kitties killed and ate as many as 135 railway workers.

This overgrown Illinois water park offers a whole new type of adventure.

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

One of the largest pieces of scientific equipment ever carried on a NASA space shuttle sits in a Chicago alley.

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

River pirates, murderous bandits, and serial killers used this Illinois cave as their debauched hideout.

The world's only known button museum.

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

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

This museum celebrating the almighty dollar lets visitors literally stand in the shadow of a million bucks.

Years of archaeology, just chillin' by the water cooler.

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