Dag Hammarskjold was a Swedish diplomat, economist, and author who served as the second Secretary-General of the United Nations, from April 1953 until his death in a plane crash in September 1961. At the age of 47 years upon his appointment, Hammarskjold was the youngest to have held the post.
Additionally, he is one of only four people to be awarded a posthumous Nobel Prize and was the only United Nations Secretary-General to die while in office. He was killed in a Douglas DC-6 airplane crash en route to cease-fire negotiations. Hammarskjold has been referred to as one of the two best secretary-generals of the United Nations, and his appointment has been mentioned as the most notable success for the UN. United States President John F. Kennedy called Hammarskjold “the greatest statesman of our century”.