Dag Hjalmar Agne Carl Hammarskjöld (/ˈhæmərʃʊld/ HAM-ər-shuuld, Swedish: [ˈdɑːɡ ˈhâmːarˌɧœld]; 29 July 1905 – 18 September 1961) was a Swedish economist and diplomat who served as the second Secretary-General of the United Nations from April 1953 until his death in a plane crash in September 1961. As of 2022, he remains the youngest person to have held the post, having been only 47 years old when he was appointed.