1950’s Nuclear Accident Remembered by Greenpeace
Perhaps the biggest nuclear accident occurred in Russia in 1957. The accident, virtually unknown because of secrecy at the time, wasn’t announced until 1989.
For an AP article about the accident memorial and Greenpeace protest, see:
http://www.iht.com/articles/ap/2007/09/29/europe/EU-GEN-Russia-Nuclear-Accident.php