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

An abandoned relic of the city's failed experiment with below ground transit.

A late sculptor's last project was to turn this abandoned cement factory into a castle-themed amusement park.

An abandoned factory along the Mississippi coated by a giant mural.

An abandoned meat mecca now serves as an excellent locale for urban exploration.

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

An abandoned observatory in the middle of the Illinois prairie.

A once-booming Mississippi River town with a history of racial violence is now eerie and mostly abandoned.

This abandoned cemetery has a dark past of bodies buried over bodies.

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

A collection of sculptures and trails that appear to change with the seasons.

Where hikers on the Tecumseh Trail can exchange a dirty sock for a free geode.

Tucked away in the forests of Indiana resides an abandoned waterslide that is now a popular graffiti haunt.

If astronomy had a ghost, it would look like this observatory.

A stunning, abandoned limestone quarry in southern Indiana provided the stone to erect the Empire State Building.

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

A lesser-known part of the Kinsey Institute is this impressive collection of art, artifacts, and material culture related to human sexuality.