constitution imaginable, though there was some skepticism. Stalin's Great Purge resulted in the detainment or execution of many ‘Old Bolsheviks’ who had participated in the October Revolution with Lenin. According to declassified Soviet archives, the NKVD arrested more than one and a half million people in 1937 and 1938, of whom 681,692 were shot. Over those two years, there were an average of over one thousand executions a day. In 1939, after attempts to form a military alliance with Britain and France against Germany failed, the Soviet Union made a dramatic shift towards Nazi Germany. Almost a year after Britain and France had concluded the Munich Agreement with Germany, the Soviet Union made agreements with Germany as well, both militarily and economically during extensive talks. The two countries concluded the Molotov–Ribbentrop Pact and the on 23 August 1939. The former made possible the Soviet occupation of Lithuania, Latvia, Estonia, Bessarabia, northern Bukovina, and eastern Poland. On 1 September, Germany invaded Poland and on the 17th the Soviet Union invaded Poland as well. On 6 October, Poland fell and part of the Soviet occupation zone was then handed over to Germany. On 10 October, the Soviet Union and Lithuania signed an agreement whereby the Soviet Union transferred Polish sovereignty over the Vilna region to Lithuania, and on 28 October the boundary between the Soviet occupation zone and the new territory of Lithuania was officially demarcated. On 1 November, the Soviet Union annexed Western Ukraine, followed by Western Belarus on the 2nd. In late November, unable to coerce the Republic of Finland by diplomatic means into moving its border back from Leningrad, Stalin ordered the invasion of Finland. On 14 December 1939, the Soviet Union was expelled from the League of Nations for invading 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, the USSR signed the Soviet–Japanese Neutrality Pact with Japan, recognizing the territorial integrity of Manchukuo, a Japanese puppet state. World War II Germany broke the Molotov–Ribbentrop Pact and invaded the Soviet Union on 22 June 1941 starting what was known in the USSR as the Great Patriotic War. The Red Army stopped the seemingly invincible German Army at the Battle of Moscow. The Battle of Stalingrad, which lasted from late 1942 to early 1943, dealt a severe blow to Germany from