The Wikipedia article of the day for March 13, 2018 is Winter War.
The Winter War (30 November 1939 – 13 March 1940) began when the Soviet Union (USSR) invaded Finland three months after the outbreak of World War II. The USSR had sought to annex Finnish territory, including land near Leningrad, 32 km (20 mi) from the border. After Finland refused, the USSR attacked with more than twice as many soldiers, thirty times as many aircraft, and a hundred times as many tanks as the defending forces. The Red Army had been crippled by Joseph Stalin’s Great Purge and the Finnish Defence Forces repelled the invasion in temperatures down to −43 °C (−45 °F) for much longer than expected. A reorganized Soviet offensive broke through in February 1940 and forced the Finns to seek peace. Finland ceded 11 percent of its territory, but retained sovereignty. Soviet casualties have been estimated at 321,000 to 381,000, compared to Finnish casualties of 70,000. The poor performance of the Red Army encouraged Adolf Hitler to consider an attack on the USSR. After a 15-month lull called the Interim Peace, the Continuation War and Operation Barbarossa began in June 1941.