Former Soviet union president Mikhail Gorbachev,who ended the cold war and left failed to prevent the collapse of Soviet union died on Tuesday at age 91 , according to Russian news agency . He was the last leader of United Soviet socialist Republic (USSR).He was a young and dynamic leader who wanted to reform the communist regime along the lines of democratic principles by giving some freedom to citizen.He launched radical reforms to reduce party control of the Government apparatus.Notably , thousands of political prisoners and their dissidents were released during his rule.Gorbachev is accredited with the success of nuclear disarmament agreement with United States of America which won him Nobel peace prize.