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Mannerheim Line

Finnish defense system

Quick Summary

The Mannerheim Line was a defensive fortification system built by Finland across the Karelian Isthmus. It was intended to protect Finland from potential Soviet aggression, particularly from Leningrad. Constructed under the leadership of Carl Gustaf Mannerheim, who later became Finland's president, the line featured reinforced concrete fortifications and machine gun pillboxes.12

During the Russo-Finnish War of 1939-1940, the Mannerheim Line successfully halted the initial Soviet advance, despite the Soviet Union deploying significantly larger forces. However, after suffering heavy losses, the Soviets launched a major assault in February 1940, eventually breaching the line. This led to Finland ceding territory to the Soviet Union in the subsequent peace treaty.12

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