On Aug. 23, 1939, the USSR signed a nonaggression pact with Nazi Germany,
which shortly afterward, invaded Poland. Soviet troops entered Poland in Sept
of 1939, which was divided between Germany and the USSR. The Soviet Union
then 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.
