A unique collection of military history dating back to the American Revolution.

This grave marks the final resting place of pioneer John Chapman, better known as Johnny Appleseed.

Discover a beautiful natural paradise, minutes away from a thriving city.

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

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

World's second largest particle accelerator, where nature reveals its secrets.

This former nursery supplied plants for the creation of Chicago's largest park.

The final resting place of the world's first nuclear reactor.

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

This $3 million model train takes you through Chicago, Seattle, and the thousands of miles in between.

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

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

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

A small abandoned and abused cemetery that has become a magnet for ghost hunters.

What was once the second largest steel mill in the US is now a sprawling complex of modern ruins.

A historic and oft-filmed prison stands in a Chicago suburb.

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

The site of a 19th century "dream city" that almost rivaled Chicago before being swallowed by the Indiana sand dunes.

A chilling disappearance (and rescue) of a child uncovers a geological mystery.

A unique outdoor timepiece at a "clothing-optional" resort.

The large rock formation where the Shawnee prophet Tenskwatawa stood and encouraged his warriors during the Battle of Tippecanoe.

The body of one of the world's most famous outlaws is covered in cement and iron to prevent it from being stolen.

A medical facility that has been kept frozen in time.

This hidden stream beneath Indianapolis makes an appearance in the best-selling novel "Underground Airlines."