A hidden network of subterranean passageways lies tangled beneath Indianapolis' bustling City Market.

You were once able to challenge a chicken to tic-tac-toe at this park, which is now converted into the Aikman Wildlife Adventure.

Once known as the Illinois Asylum for the Incurable Insane.

The NBA player's elaborate former home is now a ghost of its old glory.

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

A onetime gangsters' hideaway where you can dine on steaks, fine wines, and cigars just like they once did.

A century-old network of freight tunnels underneath the city's historic business district.

A wondrously macabre treasury of obscure antiques and unusual oddities.

This graveyard is home to the so-called "Witch's Circle."

See where Bill Murray kidnapped a hapless Punxsutawney Phil.

This art gallery and oddities boutique bewitches visitors with a trove of occult trinkets and eccentric antiques, work by an ever-changing roster of underground artists, and classes in tarot and other mystic arts.

This unassuming city park is home to three different types of Native American mounds.

At the largest railway museum in the United States, you can see everything from an early steam engine to a functioning Thomas the Tank Engine.

The only place in America where anyone who wants can shovel coal aboard an antique train.

A mythical bird etched into the face of a rock doubles as the mascot for a nearby school.

A former atom smasher turned into an art gallery.

An amazing collection of scale model ships.

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

The world's third-largest scale model of the planets.

The famous author's birthplace is preserved in a town that he once described as narrow-minded.

This deceivingly ordinary warehouse hides an enormous collection of pop culture treasures.

First known as the "Sample House," this construction mash-up was meant to be a living catalogue of building styles.

This architectural stunner is one of the few surviving Egyptian Revival theaters in the U.S.

An abandoned observatory in the middle of the Illinois prairie.