Question: Who created the political borders of the continent that contains the river that serves as drainage for the southwest plain of the Congo?

full_context: Document 1: Africa: In the late 19th century, the European imperial powers engaged in a major territorial scramble and occupied most of the continent, creating many colonial territories, and leaving only two fully independent states: Ethiopia (known to Europeans as ``Abyssinia ''), and Liberia. Egypt and Sudan were never formally incorporated into any European colonial empire; however, after the British occupation of 1882, Egypt was effectively under British administration until 1922.
Document 2: Republic of the Congo: Congo is located in the central-western part of sub-Saharan Africa, along the Equator, lying between latitudes 4°N and 5°S, and longitudes 11° and 19°E. To the south and east of it is the Democratic Republic of Congo. It is also bounded by Gabon to the west, Cameroon and the Central African Republic to the north, and Cabinda (Angola) to the southwest. It has a short coast on the Atlantic Ocean.
Document 3: Modern history: The major European powers laid claim to the areas of Africa where they could exhibit a sphere of influence over the area. These claims did not have to have any substantial land holdings or treaties to be legitimate. The European power that demonstrated its control over a territory accepted the mandate to rule that region as a national colony. The European nation that held the claim developed and benefited from their colony’s commercial interests without having to fear rival European competition. With the colonial claim came the underlying assumption that the European power that exerted control would use its mandate to offer protection and provide welfare for its colonial peoples, however, this principle remained more theory than practice. There were many documented instances of material and moral conditions deteriorating for native Africans in the late nineteenth and early twentieth centuries under European colonial rule, to the point where the colonial experience for them has been described as "hell on earth."
Document 4: Scramble for Africa: The ``Scramble for Africa ''was the occupation, division, and colonisation of African territory by European powers during the period of New Imperialism, between 1881 and 1914. It is also called the Partition of Africa and by some the Conquest of Africa. In 1870, only 10 percent of Africa was under European control; by 1914 it had increased to almost 90 percent of the continent, with only Ethiopia (Abyssinia), the Dervish state (a portion of present - day Somalia) and Liberia still being independent.
Document 5: Mitumba Mountains: The Mitumba Mountain range stretches along the Western Rift Valley in Eastern Congo (DRC), west of lake Tanganyika. The two main peaks, Mount Kahuzi (3,308 m) and Mount Biéga (2,790 m) are extinct volcanoes.
Document 6: Modern history: From the 1880s to 1914, the European powers expanded their control across the African continent, competing with each other for Africa’s land and resources. Great Britain controlled various colonial holdings in East Africa that spanned the length of the African continent from Egypt in the north to South Africa. The French gained major ground in West Africa, and the Portuguese held colonies in southern Africa. Germany, Italy, and Spain established a small number of colonies at various points throughout the continent, which included German East Africa (Tanganyika) and German Southwest Africa for Germany, Eritrea and Libya for Italy, and the Canary Islands and Rio de Oro in northwestern Africa for Spain. Finally, for King Leopold (ruled from 1865–1909), there was the large “piece of that great African cake” known as the Congo, which, unfortunately for the native Congolese, became his personal fiefdom to do with as he pleased in Central Africa. By 1914, almost the entire continent was under European control. Liberia, which was settled by freed American slaves in the 1820s, and Abyssinia (Ethiopia) in eastern Africa were the last remaining independent African states. (John Merriman, A History of Modern Europe, Volume Two: From the French Revolution to the Present, Third Edition (New York: W. W. Norton & Company, 2010), pp. 819–859).
Document 7: Modern history: At the time of the Berlin Conference, Africa contained one-fifth of the world’s population living in one-quarter of the world’s land area. However, from Europe's perspective, they were dividing an unknown continent. European countries established a few coastal colonies in Africa by the mid-nineteenth century, which included Cape Colony (Great Britain), Angola (Portugal), and Algeria (France), but until the late nineteenth century Europe largely traded with free African states without feeling the need for territorial possession. Until the 1880s most of Africa remained unchartered, with western maps from the period generally showing blank spaces for the continent’s interior.
Document 8: Mayombe: Mayombe (or Mayumbe) is a geographic area on the western coast of Africa occupied by low mountains extending from the mouth of the Congo River in the south to the Kouilou-Niari River to the north. The area includes parts of the Democratic Republic of the Congo, Angola (Cabinda Province), the Republic of the Congo and Gabon.
Document 9: Republic of the Congo: The Republic of the Congo's sparse population is concentrated in the southwestern portion of the country, leaving the vast areas of tropical jungle in the north virtually uninhabited. Thus, Congo is one of the most urbanized countries in Africa, with 70% of its total population living in a few urban areas, namely in Brazzaville, Pointe-Noire or one of the small cities or villages lining the 534-kilometre (332 mi) railway which connects the two cities. In rural areas, industrial and commercial activity has declined rapidly in recent years, leaving rural economies dependent on the government for support and subsistence.
Document 10: Republic of the Congo: The Republic of the Congo (French: République du Congo), also known as Congo, Congo Republic, West Congo[citation needed], or Congo-Brazzaville, is a country located in Central Africa. It is bordered by five countries: Gabon to the west; Cameroon to the northwest; the Central African Republic to the northeast; the Democratic Republic of the Congo to the east and south; and the Angolan exclave of Cabinda to the southwest.
Document 11: Republic of the Congo: Since the country is located on the Equator, the climate is consistent year-round, with the average day temperature being a humid 24 °C (75 °F) and nights generally between 16 °C (61 °F) and 21 °C (70 °F). The average yearly rainfall ranges from 1,100 millimetres (43 in) in south in the Niari Valley to over 2,000 millimetres (79 in) in central parts of the country. The dry season is from June to August while in the majority of the country the wet season has two rainfall maxima: one in March–May and another in September–November.
Document 12: Congo River: Railways now bypass the three major falls, and much of the trade of Central Africa passes along the river, including copper, palm oil (as kernels), sugar, coffee, and cotton. The river is also potentially valuable for hydroelectric power, and the Inga Dams below Pool Malebo are first to exploit the Congo river.
Document 13: Geography of Angola: Angola is located on the western Atlantic Coast of Central Africa between Namibia and the Republic of the Congo. It also is bordered by the Democratic Republic of the Congo and Zambia to the east. The country consists of a sparsely watered and somewhat sterile coastal plain extending inland for a distance varying from . Slightly inland and parallel to the coast is a belt of hills and mountains and behind those a large plateau. The total land size is . It has an Exclusive Economic Zone of .
Document 14: Yumbi: Yumbi is a town and territory in Plateaux District of Bandundu Province in the Democratic Republic of the Congo. It lies on the eastern bank of the Congo River between Bolobo and Lukolela.
Document 15: Republic of the Congo: The southwest of the country is a coastal plain for which the primary drainage is the Kouilou-Niari River; the interior of the country consists of a central plateau between two basins to the south and north. Forests are under increasing exploitation pressure.
ground_truth: European imperial powers
sub_queries: Which river serves as drainage for the southwest plain of the Congo? Answer: Kouilou-Niari River
Kouilou-Niari River >> continent Answer: Africa
who created the borders of Africa 's countries Answer: European imperial powers