Exactly 55 years ago: U Thant of Burma is sworn in as Acting United Nations Secretary General. He succeeded Dag Hammarskjold of Sweden who had died in a mysterious plane crass en route to the Congo. This was during the height of the Cold War. The Soviet Union had been insisting on a 'Troika' formula of three Secretaries-General, something which would have effectively destroyed the institution. U Thant emerged as the only person both Moscow and Washington could agree on as a temporary replacement