Today marks the 20th Anniversary of the Chernobyl nuclear disaster. At 3:23p April 25th, 1986 (Pacific) or 1:23a April 26th, 1986 (Chernobyl), Chernobyl's number four reactor had a melt down. The reactor went out of control creating explosions and a fireball which blew off the reactor's heavy steel and concrete lid, spewing radioactive clouds over the former USSR (now Ukraine) and much of Europe for ten days. The Chernobyl accident killed more than 30 people instantly, and as a result of the high radiation levels in the surrounding 32 kilometer radius, 135,000 people had to be evacuated. There is no doubt that Chernobyl is the worlds worst nuclear disaster.