Question: When did the country Dagda is located become part of the Soviet Union?

full_context: Document 1: Latvian Soviet Socialist Republic: Following the Welles Declaration of July 23, 1940, the annexation of Latvia into the Soviet Union (USSR) on 5 August 1940 was not recognized as legitimate by the United States, the European Community, and recognition of it as the nominal fifteenth constituent republic of the USSR was withheld for five decades. Its territory was subsequently conquered by Nazi Germany in June -- July 1941, before being retaken by the Soviets in 1944 -- 1945. Nevertheless, Latvia continued to exist as a de jure independent country with a number of countries continued to recognize Latvian diplomats and consuls who still functioned in the name of their former governments.
Document 2: Dagda, Latvia: Dagda () is a town in eastern Latvia, near the country's border with Belarus. It is the administrative center of Dagda municipality.
Document 3: Daday: Daday is a town and district of the Kastamonu Province in the Black Sea region of Turkey. It is located at 30 km west of Kastamonu. According to the 2000 census, population of the district is 11,181 of which 4,625 live in the town of Daday. The district covers an area of , and the town lies at an elevation of . The terrain is mainly mountainous and covered with pine trees. The town is located in a valley on a small river. The economy is based primarily on agriculture and forestry products. Daday is known for its famous "etliekmek", the traditional food of the Kastamonu region.
Document 4: Molotov–Ribbentrop Pact: In mid-June 1940, when international attention was focused on the German invasion of France, Soviet NKVD troops raided border posts in Lithuania, Estonia and Latvia. State administrations were liquidated and replaced by Soviet cadres, in which 34,250 Latvians, 75,000 Lithuanians and almost 60,000 Estonians were deported or killed. Elections were held with single pro-Soviet candidates listed for many positions, with resulting peoples assemblies immediately requesting admission into the USSR, which was granted by the Soviet Union. The USSR annexed the whole of Lithuania, including the Scheschupe area, which was to be given to Germany.
Document 5: Belarus: Belarus (; , ), officially the Republic of Belarus (, ), formerly known by its Russian name Byelorussia or Belorussia (), is a landlocked country in Eastern Europe bordered by Russia to the northeast, Ukraine to the south, Poland to the west, and Lithuania and Latvia to the northwest. Its capital and most populous city is Minsk. Over 40% of its is forested. Its major economic sectors are service industries and manufacturing. Until the 20th century, different states at various times controlled the lands of modern-day Belarus, including the Principality of Polotsk (11th to 14th centuries), the Grand Duchy of Lithuania, the Polish–Lithuanian Commonwealth, and the Russian Empire.
Document 6: Estonia: In 1989, during the "Singing Revolution", in a landmark demonstration for more independence, more than two million people formed a human chain stretching through Lithuania, Latvia and Estonia, called the Baltic Way. All three nations had similar experiences of occupation and similar aspirations for regaining independence. The Estonian Sovereignty Declaration was issued on 16 November 1988. On 20 August 1991, Estonia declared formal independence during the Soviet military coup attempt in Moscow, reconstituting the pre-1940 state. The Soviet Union recognised the independence of Estonia on 6 September 1991. The first country to diplomatically recognise Estonia's reclaimed independence was Iceland. The last units of the Russian army left on 31 August 1994.
Document 7: Dissolution of the Soviet Union: On June 14, 1987, about 5,000 people gathered again at Freedom Monument in Riga, and laid flowers to commemorate the anniversary of Stalin's mass deportation of Latvians in 1941. This was the first large demonstration in the Baltic republics to commemorate the anniversary of an event contrary to official Soviet history. The authorities did not crack down on demonstrators, which encouraged more and larger demonstrations throughout the Baltic States. The next major anniversary after the August 23 Molotov Pact demonstration was on November 18, the date of Latvia’s independence in 1918. On November 18, 1987, hundreds of police and civilian militiamen cordoned off the central square to prevent any demonstration at Freedom Monument, but thousands lined the streets of Riga in silent protest regardless.
Document 8: Estonia: On 6 August 1940, Estonia was annexed by the Soviet Union as the Estonian SSR. The provisions in the Estonian constitution requiring a popular referendum to decide on joining a supra-national body were ignored. Instead the vote to join the Soviet Union was taken by those elected in the elections held the previous month. Additionally those who had failed to do their "political duty" of voting Estonia into the USSR, specifically those who had failed to have their passports stamped for voting, were condemned to death by Soviet tribunals. The repressions followed with the mass deportations carried out by the Soviets in Estonia on 14 June 1941. Many of the country's political and intellectual leaders were killed or deported to remote areas of the USSR by the Soviet authorities in 1940–1941. Repressive actions were also taken against thousands of ordinary people.
Document 9: Rēzekne: Rēzekne (Latgalian "Rēzekne" or "Rēzne" , ; see other names) is a city in the Rēzekne River valley in Latgale region of eastern Latvia. It is called "The Heart of Latgale" (Latvian "Latgales sirds", Latgalian "Latgolys sirds"). Built on seven hills, Rēzekne is situated east of Riga, and west of the Latvian-Russian border, at the intersection of the Moscow – Ventspils and Warsaw – Saint Petersburg Railways. It has a population of 31,216 (2016) making it the 7th largest city in Latvia.
Document 10: Šķirotava: Šķirotava is a neighbourhood of Riga, the capital of Latvia. It is located in the Latgale Suburb of Riga close to the city's southeastern border. The perfect way to get there is by Rīgas Satiksme companies buses: N3, N13, N15, N20, N34, N47, N48, N50, N52 or trolleybuses N16 and N22. Do not confuse with Šķirotava station.
Document 11: Gmina Włodawa: Gmina Włodawa is a rural gmina (administrative district) in Włodawa County, Lublin Voivodeship, in eastern Poland, on the border with Belarus and Ukraine. Its seat is the town of Włodawa, although the town is not part of the territory of the gmina.
Document 12: Latvia: Latvia ( or ; , ), officially the Republic of Latvia (, ), is a country in the Baltic region of Northern Europe. Since its independence, Latvia has been referred to as one of the Baltic states. It is bordered by Estonia to the north, Lithuania to the south, Russia to the east, and Belarus to the southeast, and shares a maritime border with Sweden to the west. Latvia has 1,957,200 inhabitants and a territory of . The country has a temperate seasonal climate.
Document 13: History of Latvia: The First Latvian National Awakening began in the 1850s and continued to bear fruit after World War I when, after two years of struggle in the Latvian War of Independence, Latvia finally won sovereign independence, as recognised by Soviet Russia in 1920 and by the international community in 1921. The Constitution of Latvia was adopted in 1922. Political instability and effects of the Great Depression led to the May 15, 1934 coup d'état by Prime Minister Kārlis Ulmanis. Latvia's independence was interrupted in June -- July 1940, when the country was occupied and incorporated into the Soviet Union. In 1941 it was invaded and occupied by Nazi Germany, then reconquered by the Soviets in 1944 -- 45.
Document 14: Baldonas: Baldonas is a village in Penkule Parish and Dobele Municipality in the historical region of Zemgale, and the Zemgale Planning Region in Latvia.
Document 15: Post-Soviet states: The post-Soviet states, also collectively known as the former Soviet Union (FSU) or former Soviet Republics, are the 15 independent states that emerged from the Union of Soviet Socialist Republics in its dissolution in December 1991, with Russia internationally recognised as the successor state to the Soviet Union. On March 11, 1990, Lithuania was the first to declare its independence, with Estonia and Latvia following suit in August 1991. All three Baltic states claimed continuity from the original states that existed prior to their annexation by the Soviet Union in 1944 and were admitted to the United Nations on 17 September 1991. The remaining 12 republics all subsequently seceded. 12 of the 15 states, excluding the Baltic states, initially formed the CIS and most joined CSTO, while the Baltic states focused on European Union and NATO membership.
ground_truth: 5 August 1940
sub_queries: Dagda >> country Answer: Latvia
when did Latvia become part of the soviet union Answer: 5 August 1940