Title: History of Russia
Content: December 1939 the USSR invaded Finland, beginning a campaign known as the Winter War (1939–40). The war took a heavy death toll on the Red Army but forced Finland to sign a Moscow Peace Treaty and cede the Karelian Isthmus and Ladoga Karelia. In summer 1940 the USSR issued an ultimatum to Romania forcing it to cede the territories of Bessarabia and Northern Bukovina. At the same time, the Soviet Union also occupied the three formerly independent Baltic states (Estonia, Latvia and Lithuania). The peace with Germany was tense, as both sides were preparing for the military conflict, and abruptly

Title: World War II by country
Content: Mongolia between May–August, 1939. Later that year, protected with the Molotov–Ribbentrop Pact, it invaded eastern Poland about three weeks after the Germans invaded the west of the country. During the next eleven months the Soviets occupied and annexed the Baltic states. The Soviet Union supported Germany in the war effort against Western Europe through the 1939 German–Soviet Commercial Agreement and larger 1940 German–Soviet Commercial Agreement with supplies of raw materials that were otherwise blocked by the British naval blockade. Following Finland's refusal of Soviet demands for military bases and a territorial swap, the Soviet Union invaded on 30 November 1939,

Title: Aftermath of the Winter War
Content: summer 1940, the Soviet Union occupied the Baltic states of Estonia, Latvia, and Lithuania. During 1940, the Finns and Swedes successfully negotiated a military alliance, but the negotiations ended once it became clear that both Germany and the Soviet Union opposed such an alliance. During the four months of fighting, the Soviet Army suffered massive losses. One Red Army General, looking at a map of the territory just conquered, is said to have remarked: "We have won just about enough ground to bury our dead." The official Soviet figure, issued just after the war, listed 48,745 dead and 150,863 wounded.

Title: Axis powers
Content: military aid to the Second Spanish Republic, against Spanish Nationalist forces, which were assisted by Germany and Italy. However, the Nationalist forces were victorious. The Soviets suffered another political defeat when their ally Czechoslovakia was partitioned and taken over by Germany in 1938–39. In 1938 and 1939, the USSR fought and defeated Japan in two separate border conflicts, at Lake Khasan and Khalkhin Gol. The latter was a major Soviet victory that led the Japanese Army to avoid war with the Soviets and instead call for expansion south. In 1939 the Soviet Union considered forming an alliance with either Britain

Title: Soviet Union
Content: eastern Poland. In late November, unable to coerce the Republic of Finland by diplomatic means into moving its border back from Leningrad, Joseph Stalin ordered the invasion of Finland. In the east, the Soviet military won several decisive victories during border clashes with the Empire of Japan in 1938 and 1939. However, in April 1941, USSR signed the Soviet–Japanese Neutrality Pact with the Japan, recognizing the territorial integrity of Manchukuo, a Japanese puppet state. Although it has been debated whether the Soviet Union intended to invade Germany once it was strong enough, Germany itself broke the treaty and invaded the

Question: Which country was defeated by the USSR in the Winter War of 1939?
Answer: Finland