It's a well-known fact: don't leave kids in cars in the heat. You hear it all the time. Sadly, not everyone gets the message.

Maybe that's why Kars4Kids created this unusual reminder.

The premise of this experiment: any adult who can last 10 minutes in a car with the windows closed would get $100.

That may be some cold hard cash, but no one could take the heat. That's right -- not one person could make it all 10 minutes.

As one man who participated said, "That was one of the worst things I've ever gone through in my life."

If you see adults struggling, just imagine the agony children experience, since they don't have the ability to let themselves out of a car.

To make sure people don't leave kids in hot cars, Kard4Kids has also created an app, which "is designed to alert drivers when they leave their cars to remember there is a baby in the backseat." Knowing how dangerous this trend can be, it may be worth downloading.