Russo-Finnish War
(1939 – 40) War waged by the Soviet Union against Finland at the start of
World War II, following the signing of the
German-Soviet Nonaggression Pact. When Finland refused to grant the Soviets a naval base and other concessions, Soviet troops attacked on several fronts in November 1939. The heavily outnumbered Finns under Carl Gustav Emil
Mannerheim put up a skillful defense until February 1940, when heavy Russian bombardments breached the Finns' southern defenses. A peace treaty in March 1940 ceded western Karelia to Russia and allowed construction of a Soviet naval base on the Hanko peninsula.
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