Soviet Union Invades Finland, Starting Winter War
Following the Molotov-Ribbentrop Pact and the partition of Poland, the Soviet Union sought to secure its northwestern frontier by demanding Finnish territory near Leningrad and naval bases. Finland refused concessions that would compromise its sovereignty. On November 30, 1939, the Red Army crossed the border in multiple sectors, bombed Helsinki, and launched a full-scale invasion with superior numbers and equipment. Finnish forces, though outnumbered, mounted a determined defense using guerrilla tactics, ski troops, and harsh winter conditions to inflict disproportionate casualties. The conflict, known as the Winter War, lasted until March 1940 and drew international attention to Finnish resilience. It exposed weaknesses in Soviet military preparedness ahead of World War II escalation.
