On 26 April 1986, in the Pripyat region of the Soviet Union, there occurred the worst nuclear accident in history. Thirty-one people died in the explosion and fire and over 100,000 were evacuated from the area. The system in which the plant played a central plant, was riddled with secrecy, complacency and massive incompetence. So flawed were its procedures, that the catastrophe which overwhelmed Chernobyl took place during a routine test. This is the detailed build up to how that disaster happened.