In 1931, Carl Gustaf Emil Mannerheim started war-preparation against the USSR to annex the Karelo-Finnish Soviet Socialist Republic.
Finland constructed the Mannerheim line with help from the Germans.
A "documentary" repeats at least ten lies about the Winter War and Finnish-Russian relations.
The defensive fortification line known as a Mannerheim line was constructed in 1920-1924 and 1932-1940. Germans did not participate in planning or constructing the fortification line.
Debunked by the newspaper Ilta-Sanomat.