There's a creepy alley in Chicago that has one of the most heartbreaking background stories in all of Illinois. The Alley of Death in the downtown area's theatre district was the sight of a horrific event that happened more than 100 years ago. Learn all about what caused a six-foot-high pile-up of bodies in a narrow alley. Scroll on for the whole story on the Alley of Death in Illinois.

The Alley of Death in Illinois, also known as Couch Place, has one of the most horrific backstories in Chicago's history. Discretion is advised if you get easily upset.

This slice of Illinois history began with the Iroquois Theatre, which the media claimed was fire-proof: an obvious mistake. Its first show, which was a play called Mr. Bluebird, opened on December 30, 1903, and sold out to nearly 1,800 attendants.

Constructed in haste the summer before, it seemed the threatre was not constructed well. A stage light sparked midway through the show and caught the entire backdrop on fire. Stagehands attempted to douse the flames with Kylfire, an extinguisher powder, but the flames rose too high for them to reach. As a backup, an asbestos curtain was lowered but snagged on the way down and was rendered useless.

Once people realized something was wrong, they began rushing out of the theatre only to find themselves lost or to find doors locked. Most attendants trapped on the upper levels were forced to jump or attempt to crawl across ladders hoisted over by tenants in the building next door. Unfortunately, many fell to their death.

There were several issues with the Iroquois that caused the devastation of this disaster to be so grand, and they are the reasons theatres today are equipped with better safety precautions. First of all, people could not locate emergency exits because they were not labeled. Once one was located, the door had to be opened inward, making it impossible to get through with so many people pushing behind. There was a skylight above the stage meant to be opened to let out smoke, but it would not budge and seemed to be nailed shut. Additionally, when performers and stage hands opened the backstage doors, it caused a blast of fire to burst into the house.

The fire lasted about a half hour and took the lives of more than 600 people all together. It was said that the bodies stacked six-feet high and that some lived for having their fall cushioned by those who jumped before them.

Today, the Oriental Theatre, built in 1926, sits in place of the Iroquois, and there are no markings to denote that this tragic piece of Illinois history took place.

There have been reports of an unusually cool breeze or whispers of your own name heard when walking down this alley. That doesn't stop people, though. This creepy alley is used by Chicago commuters as well as stagehands and actors for the theatre on a regular basis. Yet it's one of the most haunted places in Illinois.

While you're visiting this eerie attraction, check out the 10 haunted places in Chicago that will chill your spine.

Have you ever been down the Alley of Death in Illinois? Share your photos and experiences with us in the comments below.