A treaty between Pennsylvania and Maryland ends the Conojocular War with settlement of a boundary dispute and exchange of prisoners.

Members of Soviet politburo sign an order for the execution of 25,700 Polish intelligentsia, including 14,700 Polish POWs, known also as the Katyn massacre.

French prisoner of war General Henri Giraud escapes from his castle prison in Festung Königstein.

World War II: RMS ''Laconia'', carrying civilians, Allied soldiers and Italian POWs is torpedoed off the coast of West Africa and sinks with a heavy loss of life.

USS Grouper torpedoes ''Lisbon Maru'' not knowing she is carrying British PoWs from Hong Kong

World War II: The discovery of a mass grave of Polish prisoners of war executed by Soviet forces in the Katyń Forest Massacre is announced, alienating the Western Allies, the Polish government in exile in London, from the Soviet Union.

Vietnam War: First release of American prisoners of war from Vietnam takes place.

The Pulitzer Prize-winning photograph ''Burst of Joy'' is taken, depicting a former prisoner of war being reunited with his family.