paragraph_text: The Soviet invasion of Poland was a Soviet military operation that started without a formal declaration of war on 17 September 1939. On that morning, 16 days after Germany invaded Poland from the west, the Soviet Union invaded Poland from the east. Subsequent military operations lasted for the following 20 days and ended on 6 October 1939 with the two - way division and annexation of the entire territory of the Second Polish Republic by both Germany and the Soviet Union. The joint German - Soviet invasion of Poland was secretly agreed to following the signing of the Molotov - Ribbentrop Pact on 23 August 1939.

paragraph_text: The Molotov -- Ribbentrop Pact, also known as the Nazi -- Soviet Pact, the German -- Soviet Non-aggression Pact or the Nazi German - Soviet Pact of Aggression (officially: Treaty of Non-aggression between Germany and the Union of Soviet Socialist Republics), was a neutrality pact between Nazi Germany and the Soviet Union signed in Moscow on 23 August 1939 by foreign ministers Joachim von Ribbentrop and Vyacheslav Molotov, respectively. The pact was followed by the German - Soviet Commercial Agreement in February 1940.

paragraph_text: The Soviet Union was dissolved on December 26, 1991. It was a result of the declaration number 142 - Н of the Soviet of the Republics of the Supreme Soviet of the Soviet Union. The declaration acknowledged the independence of the former Soviet republics and created the Commonwealth of Independent States (CIS), although five of the signatories ratified it much later or did not do so at all. On the previous day, Soviet President Mikhail Gorbachev, the eighth and final leader of the Soviet Union, resigned, declared his office extinct, and handed over its powers -- including control of the Soviet nuclear missile launching codes -- to Russian President Boris Yeltsin. That evening at 7: 32, the Soviet flag was lowered from the Kremlin for the last time and replaced with the pre-revolutionary Russian flag.

paragraph_text: Endless Days is an album by German double bassist and composer Eberhard Weber recorded in Norway in 2000 and released on the ECM label.

paragraph_text: The Interim Peace (, ) was a short period in the history of Finland during the Second World War. The term is used for the time between the Winter War and the Continuation War, lasting a little over a year, from 13 March 1940 to 24 June 1941. The Moscow Peace Treaty was signed by Finland and the Soviet Union on 12 March 1940 and it ended the 105-day Winter War.

paragraph_text: Yuriy Bakalov (; born 16 January 1966 in Kiev, in the Ukrainian SSR of the Soviet Union - in present-day Ukraine) is a former Soviet and Ukrainian professional football midfielder and current Ukrainian coach.

paragraph_text: Cooperation ended in 1933, as Adolf Hitler came to power and created Nazi Germany. The countries' economic relationship dwindled at the beginning of the Nazi era, but some diplomatic initiatives continued through the 1930s, culminating with the Molotov -- Ribbentrop Pact of 1939 and various trade agreements. Few questions concerning the origins of the Second World War are more controversial and ideologically loaded than the issue of the policies of the Soviet Union under Joseph Stalin towards Nazi Germany between the Nazi seizure of power and the German invasion of the USSR on June 22, 1941.

paragraph_text: Stages of a Long Journey is a live album by German double bassist and composer Eberhard Weber recorded in Germany in 2005 and released on the ECM label.

paragraph_text: Alena Vinnitskaya ( "Aliona Vinnytska"; born Olha Viktorivna Vinnytska () on 27 December 1974, Kiev, in the Ukrainian SSR of the Soviet Union – in present-day Ukraine) is a Ukrainian singer. She is an author and performer.

paragraph_text: Systematic POW labor in the Soviet Union is associated primarily with the outcomes of World War II and covers the period of 1939-1956, from the official formation of the first POW camps, to the repatriation of the last POWs, from the Kwantung Army.

paragraph_text: Pojuschie Gitary ( , "The Singing Guitars") were the Soviet Union's first rock band to reach a phenomenal rate of success and popularity in the Soviet Union, Eastern Europe and in other countries. For that reason, they are often nicknamed "the Soviet Beatles" in a manner not that different from Hungary's Illés and Poland's Czerwone Gitary, whose name means "Red Guitars".

paragraph_text: On 14 June, while the world's attention was focused on the fall of Paris to Nazi Germany a day earlier, the Soviet military blockade on Estonia went into effect, two Soviet bombers downed the Finnish passenger aeroplane "Kaleva" flying from Tallinn to Helsinki carrying three diplomatic pouches from the US delegations in Tallinn, Riga and Helsinki. On 16 June, the Soviet Union invaded Estonia. The Red Army exited from their military bases in Estonia on 17 June. The following day, some 90,000 additional troops entered the country. In the face of overwhelming Soviet force, the Estonian government capitulated on 17 June 1940 to avoid bloodshed.

paragraph_text: Throughout the 1970s, both the Soviet Union and United States replaced old missiles and warheads with newer, more powerful and effective ones. This continued to worsen Soviet - U.S relations. On June 18, 1979, the SALT II treaty was signed in Vienna. This treaty limited both sides' nuclear arsenals and technology. However, this treaty as well as the era of the détente ended with the Soviet Union's invasion of Afghanistan in January, 1980. The United States once again significantly increased military and nuclear spending, while the Soviets were unable to respond and continued to pursue the détente.

paragraph_text: Under the 1977 Constitution of the Union of Soviet Socialist Republics (USSR), the Chairman of the Council of Ministers was the head of government and the Chairman of the Presidium of the Supreme Soviet was the head of state. The office of the Chairman of the Council of Ministers was comparable to a prime minister in the First World, whereas the office of the Chairman of the Presidium was comparable to a president in the First World. In the Soviet Union's seventy - year history there was no official leader of the Soviet Union office, but during most of that era there was a de facto top leader who usually led the country through the office of the Premier or the office of the General Secretary of the Communist Party of the Soviet Union (CPSU). In the ideology of Vladimir Lenin the head of the Soviet state was a collegiate body of the vanguard party (see What Is to Be Done?).

paragraph_text: Joseph Stalin was also upset by the results of the Munich conference. The Soviets, who had a mutual military assistance treaty with Czechoslovakia, felt betrayed by France, who also had a mutual military assistance treaty with Czechoslovakia. The British and French, however, mostly used the Soviets as a threat to dangle over the Germans. Stalin concluded that the West had actively colluded with Hitler to hand over a Central European country to the Nazis, causing concern that they might do the same to the Soviet Union in the future, allowing the partition of the USSR between the western powers and the fascist Axis. This belief led the Soviet Union to reorient its foreign policy towards a rapprochement with Germany, which eventually led to the signing of the Molotov - Ribbentrop Pact in 1939.

paragraph_text: The PTBT was signed by the governments of the Soviet Union, United Kingdom, and United States in Moscow on 5 August 1963 before being opened for signature by other countries. The treaty formally went into effect on 10 October 1963. Since then, 123 other states have become party to the treaty. Ten states have signed but not ratified the treaty.

paragraph_text: As African states became independent in the 1960s, the Soviet Union offered many of their citizens the chance to study in Russia. Over a period of 40 years, about 400,000 African students from various countries moved to Russia to pursue higher studies, including many Black Africans. This extended beyond the Soviet Union to many countries of the Eastern bloc.

paragraph_text: In the early 1930s, the worldwide Great Depression hit Germany hard, as unemployment soared and people lost confidence in the government. In January 1933, Adolf Hitler was appointed Chancellor of Germany. His Nazi Party quickly established a totalitarian regime, and Nazi Germany made increasingly aggressive territorial demands, threatening war if they were not met. Remilitarization of the Rhineland came in 1936, then annexation of Austria in the Anschluss and parts of Czechoslovakia with the Munich Agreement in 1938, and further territory of Czechoslovakia in 1939. On 1 September 1939, Germany initiated World War II in Europe with the invasion of Poland. After forming a pact with the Soviet Union in 1939, Hitler and Stalin divided Eastern Europe. After a "Phoney War" in spring 1940, the Germans swept Denmark and Norway, the Low Countries, and France, giving Germany control of nearly all of Western Europe. Hitler invaded the Soviet Union in June 1941.

paragraph_text: Year Player Country Age 1950 David Bronstein Soviet Union 26 years 1952 Tigran Petrosian Soviet Union 23 years 1955 Boris Spassky Soviet Union 18 years 1958 Bobby Fischer United States 15 years, 6 months, 1 day 1991 Judit Polgár Hungary 15 years, 4 months, 28 days 1994 Péter Lékó Hungary 14 years, 4 months, 22 days 1997 Étienne Bacrot France 14 years, 2 months, 0 days 1997 Ruslan Ponomariov Ukraine 14 years, 0 months, 17 days 1999 Bu Xiangzhi China 13 years, 10 months, 13 days 2002 Sergey Karjakin Ukraine 12 years, 7 months, 0 days

paragraph_text: The dissolution of the Soviet Union was formally enacted on December 26, 1991, as a result of the declaration no. 142-Н of the Soviet of the Republics of the Supreme Soviet of the Soviet Union. The declaration acknowledged the independence of the former Soviet republics and created the Commonwealth of Independent States (CIS), although five of the signatories ratified it much later or not at all. On the previous day, Soviet President Mikhail Gorbachev, the eighth and last leader of the Soviet Union, resigned, declared his office extinct, and handed over its powers – including control of the Soviet nuclear missile launching codes – to Russian President Boris Yeltsin. That evening at 7:32 p.m., the Soviet flag was lowered from the Kremlin for the last time and replaced with the pre-revolutionary Russian flag.

Question: What did the Soviet Union and the country of Endless Days's performer sign in 1939?
Answer: Molotov -- Ribbentrop Pact of 1939