CHERNOBYL MELTDOWN - One of the most well-known man-made disasters in history is the Chernobyl explosion, and for good reason. It all began innocently enough, with engineers conducting a standard experiment to see if the plants emergency water cooling would function in the event of a power outage. The test had been performed before, but this time there was a power surge, making it impossible for engineers to turn off Chernobyls nuclear reactors. One reactor experienced a steam buildup, roof collapse, nuclear core exposure, and radioactive material release into the atmosphere.