(17.März) From the Archive: In reopening the investigation into the mysterious plane crash that killed UN Secretary General Dag Hammarskjold in 1961, the United Nations is appealing to member states to release long-secret files related to this cold case from a tense moment in the Cold War in Africa, which Lisa Pease examined in 2013.

By Lisa Pease (Originally published on Sept. 16. 2013)