In 1920, USSR lost a war with Finland and the USSR had to shamefully sign the Treaty of Tartu
In 1931, Carl Gustaf Emil Mannerheim started war-preparation against the USSR to annex the Karelo-Finnish Soviet Socialist Republic.
A "documentary" repeats at least ten lies about the Winter War and Finnish-Russian relations.
Finland prepared to defend itself in case of war, not to attack Soviet Russia as the documentary claims. The Karelo-Finnish Soviet Socialist Republic was established only in 1940.
Debunked by the newspaper Ilta-Sanomat.