A 2,000-year-old Adena burial mound located along a busy street in Columbus, Ohio.

Also known as the Osaka Garden, this garden was originally built in 1893 as part of the World's Columbian Exposition.

A physical reminder of Earth's ancient past, this rock results from the photosynthetic processes of some of the oldest forms of life.

The final resting place of up to 6,000 Confederate soldiers, the largest mass grave in the Western Hemisphere.

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

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

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

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

This awkward aquarium sculpture is one of the strangest statues in Chicago.

To find the "unicorns of the deep" you've got to go downstairs.

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

A hollow cement depiction of time's inexorable effect on the human body.

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

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

The unluckiest U-boat in the entire German fleet is now on display in a Chicago museum.

A 19th-century horse lover's bequest led to the construction of this unique fountain in Chicago.

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