1961 — The Night the UN Lost Its Leader

On September 18, 1961, United Nations Secretary-General Dag Hammarskjöld died when his plane crashed near Ndola, in what was then Northern Rhodesia, now Zambia. He was flying to ceasefire talks with Moïse Tshombe, leader of secessionist Katanga, to try to end the Congo Crisis. All 16 people aboard the DC-6 were killed.

The cause of the crash has never been conclusively established, with theories ranging from pilot error to sabotage or an attack. Multiple UN investigations, most recently an ongoing inquiry supported by the General Assembly, have kept the question open for more than six decades. Hammarskjöld remains the only UN secretary-general to die in office, and was posthumously awarded the Nobel Peace Prize.