Moscow Russia Tourist Information and Travel Guide
On Aug. 23, 1939, the USSR signed a nonaggression pact with Nazi Germany. Shortly afterward, Germany and Russia invaded Poland.
Soviet troops entered Poland in Sept of 1939, which was divided between Germany and the USSR. The Soviet Union also occupied Lithuania, Latvia, and Estonia in 1940.
When Germany attacked the USSR on June 22, 1941, the Soviet Union was caught by surprise. By the end of 1941 the Germans had surrounded Leningrad (St. Petersburg) and were converged on Moscow.
A Soviet counter-offensive saved Moscow. By the end of the war, at least 20 million Soviet lives were lost.