The David Versus Goliath Winter War
In 1939, tiny Finland held off the Soviet Union despite the massive disparity in military power. Although the Soviets possessed far more tanks and planes, they faced humiliating losses against the outnumbered Finnish forces.
The conflict began when the Soviet Union invaded just months into World War II, expecting a swift victory. Instead, the resilient Finnish military utilized mobile tactics and deep snow to stall the superior invading force. The international community was so shocked by the aggression that the League of Nations expelled the Soviet Union. This struggle became a symbol of national defiance against overwhelming odds.
Source: Winter War