Mannerheim Line

The Mannerheim Line (Mannerheim-linja, Mannerheimlinjen) was a defensive fortification line on the Karelian Isthmus built by Finland against the Soviet Union. While this was never an officially designated name, during the Winter War it became known as the Mannerheim Line, after Finnish Army's then commander-in-chief Field Marshal Baron Carl Gustaf Emil Mannerheim. The line was constructed in two phases: 1920–1924 and 1932–1939. By November 1939, when the Winter War began, the line was by no means complete. After the October Revolution in the Russian Empire, the Finns declared independence in 1917. Although the Soviet Union recognized Finland's independence, the Finns did not trust their sincerity. The relationship between the two countries deteriorated, with Soviet Russia supporting the Red Guard during the Finnish Civil War in 1918. After the victory of the White Guard, a group of Finnish communists fled to Soviet Russia and established the Communist Party of Finland. The situation was considered dangerous for a new nation like Finland, especially as the capital of the new communist revolution was nearby Petrograd, (now Saint Petersburg). Furthermore, before the Treaty of Tartu in 1920, the border area was restless. The former general of Imperial Russia, C.G.E. Mannerheim, strongly opposed the Bolsheviks (Communists). Construction work on the Karelian Isthmus had already begun when the Bolsheviks won the Russian Civil War in 1922. The line was constructed in two phases: In 1920–1924 and 1932–1939. During the civil war of 1918, the Finnish government and high command started to develop defence plans to protect against possible attacks from the Soviet Union. The main such route was the Karelian Isthmus. The most endangered part of that isthmus was to the west, near the Gulf of Finland, the eastern part was better protected by the natural water-ways of Vuoksi, Suvanto and Taipaleenjoki. The first plans for a defensive line were commissioned by Mannerheim from the Swedish volunteer Lieutenant Colonel A.