"The earthquake and tsunami that hit northern Japan on March 11, 2011 created the worst nuclear crisis since the Chernobyl disaster. The three active reactors at the Fukushima Daiichi Nuclear Power Station 170 miles north of Tokyo suffered meltdowns after the quake knocked out the plant's power and the tsunami disabled the backup generators meant to keep cooling systems working. A series of explosions and fires led to the release of radioactive gases." (Quoted from article)