World War II
World War II known as the Second World War, was a global war that lasted from 1939 to 1945. The vast majority of the world's countries—including all the great powers—eventually formed two opposing military alliances: the Allies and the Axis. A state of total war emerged, directly involving more than 100 million people from over 30 countries; the major participants threw their entire economic and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. World War II was the deadliest conflict in human history, marked by 50 to 85 million fatalities, most of whom were civilians in the Soviet Union and China, it included massacres, the genocide of the Holocaust, strategic bombing, premeditated death from starvation and disease, the only use of nuclear weapons in war. Japan, which aimed to dominate Asia and the Pacific, was at war with China by 1937, though neither side had declared war on the other. World War II is said to have begun on 1 September 1939, with the invasion of Poland by Germany and subsequent declarations of war on Germany by France and the United Kingdom.
From late 1939 to early 1941, in a series of campaigns and treaties, Germany conquered or controlled much of continental Europe, formed the Axis alliance with Italy and Japan. Under the Molotov–Ribbentrop Pact of August 1939, Germany and the Soviet Union partitioned and annexed territories of their European neighbours, Finland and the Baltic states. Following the onset of campaigns in North Africa and East Africa, the fall of France in mid 1940, the war continued between the European Axis powers and the British Empire. War in the Balkans, the aerial Battle of Britain, the Blitz, the long Battle of the Atlantic followed. On 22 June 1941, the European Axis powers launched an invasion of the Soviet Union, opening the largest land theatre of war in history; this Eastern Front trapped most crucially the German Wehrmacht, into a war of attrition. In December 1941, Japan launched a surprise attack on the United States as well as European colonies in the Pacific. Following an immediate U. S. declaration of war against Japan, supported by one from Great Britain, the European Axis powers declared war on the U.
S. in solidarity with their Japanese ally. Rapid Japanese conquests over much of the Western Pacific ensued, perceived by many in Asia as liberation from Western dominance and resulting in the support of several armies from defeated territories; the Axis advance in the Pacific halted in 1942. Key setbacks in 1943, which included a series of German defeats on the Eastern Front, the Allied invasions of Sicily and Italy, Allied victories in the Pacific, cost the Axis its initiative and forced it into strategic retreat on all fronts. In 1944, the Western Allies invaded German-occupied France, while the Soviet Union regained its territorial losses and turned toward Germany and its allies. During 1944 and 1945 the Japanese suffered major reverses in mainland Asia in Central China, South China and Burma, while the Allies crippled the Japanese Navy and captured key Western Pacific islands; the war in Europe concluded with an invasion of Germany by the Western Allies and the Soviet Union, culminating in the capture of Berlin by Soviet troops, the suicide of Adolf Hitler and the German unconditional surrender on 8 May 1945.
Following the Potsdam Declaration by the Allies on 26 July 1945 and the refusal of Japan to surrender under its terms, the United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki on 6 and 9 August respectively. With an invasion of the Japanese archipelago imminent, the possibility of additional atomic bombings, the Soviet entry into the war against Japan and its invasion of Manchuria, Japan announced its intention to surrender on 15 August 1945, cementing total victory in Asia for the Allies. Tribunals were set up by fiat by the Allies and war crimes trials were conducted in the wake of the war both against the Germans and the Japanese. World War II changed the political social structure of the globe; the United Nations was established to foster international co-operation and prevent future conflicts. The Soviet Union and United States emerged as rival superpowers, setting the stage for the nearly half-century long Cold War. In the wake of European devastation, the influence of its great powers waned, triggering the decolonisation of Africa and Asia.
Most countries whose industries had been damaged moved towards economic expansion. Political integration in Europe, emerged as an effort to end pre-war enmities and create a common identity; the start of the war in Europe is held to be 1 September 1939, beginning with the German invasion of Poland. The dates for the beginning of war in the Pacific include the start of the Second Sino-Japanese War on 7 July 1937, or the Japanese invasion of Manchuria on 19 September 1931. Others follow the British historian A. J. P. Taylor, who held that the Sino-Japanese War and war in Europe and its colonies occurred and the two wars merged in 1941; this article uses the conventional dating. Other starting dates sometimes used for World War II include the Italian invasion of Abyssinia on 3 October 1935; the British historian Antony Beevor views the beginning of World War II as the Battles of Khalkhin Gol fought between Japan and the fo
A river mouth is the part of a river where the river debouches into another river, a lake, a reservoir, a sea, or an ocean. The water from a river can enter the receiving body in a variety of different ways; the motion of a river is influenced by the relative density of the river compared to the receiving water, the rotation of the earth, any ambient motion in the receiving water, such as tides or seiches. If the river water has a higher density than the surface of the receiving water, the river water will plunge below the surface; the river water will either form an underflow or an interflow within the lake. However, if the river water is lighter than the receiving water, as is the case when fresh river water flows into the sea, the river water will float along the surface of the receiving water as an overflow. Alongside these advective transports, inflowing water will diffuse. At the mouth of a river, the change in flow condition can cause the river to drop any sediment it is carrying; this sediment deposition can generate a variety of landforms, such as deltas, sand bars and tie channels.
Many places in the United Kingdom take their names from their positions at the mouths of rivers, such as Plymouth and Great Yarmouth. Confluence River delta Estuary Liman
Ukraine, sometimes called the Ukraine, is a country in Eastern Europe. Excluding Crimea, Ukraine has a population of about 42.5 million, making it the 32nd most populous country in the world. Its capital and largest city is Kiev. Ukrainian is the official language and its alphabet is Cyrillic; the dominant religions in the country are Greek Catholicism. Ukraine is in a territorial dispute with Russia over the Crimean Peninsula, which Russia annexed in 2014. Including Crimea, Ukraine has an area of 603,628 km2, making it the largest country within Europe and the 46th largest country in the world; the territory of modern Ukraine has been inhabited since 32,000 BC. During the Middle Ages, the area was a key centre of East Slavic culture, with the powerful state of Kievan Rus' forming the basis of Ukrainian identity. Following its fragmentation in the 13th century, the territory was contested and divided by a variety of powers, including Lithuania, Austria-Hungary, the Ottoman Empire and Russia. A Cossack republic emerged and prospered during the 17th and 18th centuries, but its territory was split between Poland and the Russian Empire, merged into the Russian-dominated Soviet Union in the late 1940s as the Ukrainian Soviet Socialist Republic.
In 1991 Ukraine gained its independence from the Soviet Union in the aftermath of its dissolution at the end of the Cold War. Before its independence, Ukraine was referred to in English as "The Ukraine", but most sources have since moved to drop "the" from the name of Ukraine in all uses. Following its independence, Ukraine declared itself a neutral state. In 2013, after the government of President Viktor Yanukovych had decided to suspend the Ukraine-European Union Association Agreement and seek closer economic ties with Russia, a several-months-long wave of demonstrations and protests known as the Euromaidan began, which escalated into the 2014 Ukrainian revolution that led to the overthrow of Yanukovych and the establishment of a new government; these events formed the background for the annexation of Crimea by Russia in March 2014, the War in Donbass in April 2014. On 1 January 2016, Ukraine applied the economic component of the Deep and Comprehensive Free Trade Area with the European Union.
Ukraine is ranks 88th on the Human Development Index. As of 2018, Ukraine has the second lowest GDP per capita in Europe. At US$40, it has the lowest median wealth per adult in the world, it suffers from a high poverty rate and severe corruption. However, because of its extensive fertile farmlands, Ukraine is one of the world's largest grain exporters. Ukraine maintains the second-largest military in Europe after that of Russia; the country is home to a multi-ethnic population, 77.8 percent of whom are Ukrainians, followed by a large Russian minority, as well as Georgians, Belarusians, Crimean Tatars, Jews and Hungarians. Ukraine is a unitary republic under a semi-presidential system with separate powers: legislative and judicial branches; the country is a member of the United Nations, the Council of Europe, the OSCE, the GUAM organization, one of the founding states of the Commonwealth of Independent States. There are different hypotheses as to the etymology of the name Ukraine. According to the older widespread hypothesis, it means "borderland", while some more recent linguistic studies claim a different meaning: "homeland" or "region, country"."The Ukraine" used to be the usual form in English, but since the Declaration of Independence of Ukraine, "the Ukraine" has become less common in the English-speaking world, style-guides recommend not using the definite article.
"The Ukraine" now implies disregard for the country's sovereignty, according to U. S. ambassador William Taylor. The Ukrainian position is that the usage of "'The Ukraine' is incorrect both grammatically and politically." Neanderthal settlement in Ukraine is seen in the Molodova archaeological sites which include a mammoth bone dwelling. The territory is considered to be the location for the human domestication of the horse. Modern human settlement in Ukraine and its vicinity dates back to 32,000 BC, with evidence of the Gravettian culture in the Crimean Mountains. By 4,500 BC, the Neolithic Cucuteni–Trypillia culture flourished in wide areas of modern Ukraine including Trypillia and the entire Dnieper-Dniester region. During the Iron Age, the land was inhabited by Cimmerians and Sarmatians. Between 700 BC and 200 BC it was Scythia. Beginning in the sixth century BC, colonies of Ancient Greece, Ancient Rome and the Byzantine Empire, such as Tyras and Chersonesus, were founded on the northeastern shore of the Black Sea.
These colonies thrived well into the 6th century AD. The Goths stayed in the area but came under the sway of the Huns from the 370s AD. In the 7th century AD, the territory of eastern Ukraine was the centre of Old Great Bulgaria. At the end of the century, the majority of Bulgar tribes migrated in different directions, the Khazars took over much of the land. In the 5th and 6th centuries, the Antes were located in the territory of; the Antes were the ancestors of Ukrainians: White Croats, Polans, Dulebes and Tiverians. Migrations from Ukraine throughout the Balkans established many Southern Slavic nations. Northern migrations, reaching to the Ilmen l
Russia the Russian Federation, is a transcontinental country in Eastern Europe and North Asia. At 17,125,200 square kilometres, Russia is by far or by a considerable margin the largest country in the world by area, covering more than one-eighth of the Earth's inhabited land area, the ninth most populous, with about 146.77 million people as of 2019, including Crimea. About 77 % of the population live in the European part of the country. Russia's capital, Moscow, is one of the largest cities in the world and the second largest city in Europe. Extending across the entirety of Northern Asia and much of Eastern Europe, Russia spans eleven time zones and incorporates a wide range of environments and landforms. From northwest to southeast, Russia shares land borders with Norway, Estonia, Latvia and Poland, Ukraine, Azerbaijan, China and North Korea, it shares maritime borders with Japan by the Sea of Okhotsk and the U. S. state of Alaska across the Bering Strait. However, Russia recognises two more countries that border it, Abkhazia and South Ossetia, both of which are internationally recognized as parts of Georgia.
The East Slavs emerged as a recognizable group in Europe between the 3rd and 8th centuries AD. Founded and ruled by a Varangian warrior elite and their descendants, the medieval state of Rus arose in the 9th century. In 988 it adopted Orthodox Christianity from the Byzantine Empire, beginning the synthesis of Byzantine and Slavic cultures that defined Russian culture for the next millennium. Rus' disintegrated into a number of smaller states; the Grand Duchy of Moscow reunified the surrounding Russian principalities and achieved independence from the Golden Horde. By the 18th century, the nation had expanded through conquest and exploration to become the Russian Empire, the third largest empire in history, stretching from Poland on the west to Alaska on the east. Following the Russian Revolution, the Russian Soviet Federative Socialist Republic became the largest and leading constituent of the Union of Soviet Socialist Republics, the world's first constitutionally socialist state; the Soviet Union played a decisive role in the Allied victory in World War II, emerged as a recognized superpower and rival to the United States during the Cold War.
The Soviet era saw some of the most significant technological achievements of the 20th century, including the world's first human-made satellite and the launching of the first humans in space. By the end of 1990, the Soviet Union had the world's second largest economy, largest standing military in the world and the largest stockpile of weapons of mass destruction. Following the dissolution of the Soviet Union in 1991, twelve independent republics emerged from the USSR: Russia, Belarus, Uzbekistan, Azerbaijan, Kyrgyzstan, Tajikistan and the Baltic states regained independence: Estonia, Lithuania, it is governed as a federal semi-presidential republic. Russia's economy ranks as the twelfth largest by nominal GDP and sixth largest by purchasing power parity in 2018. Russia's extensive mineral and energy resources are the largest such reserves in the world, making it one of the leading producers of oil and natural gas globally; the country is one of the five recognized nuclear weapons states and possesses the largest stockpile of weapons of mass destruction.
Russia is a great power as well as a regional power and has been characterised as a potential superpower. It is a permanent member of the United Nations Security Council and an active global partner of ASEAN, as well as a member of the Shanghai Cooperation Organisation, the G20, the Council of Europe, the Asia-Pacific Economic Cooperation, the Organization for Security and Co-operation in Europe, the World Trade Organization, as well as being the leading member of the Commonwealth of Independent States, the Collective Security Treaty Organization and one of the five members of the Eurasian Economic Union, along with Armenia, Belarus and Kyrgyzstan; the name Russia is derived from Rus', a medieval state populated by the East Slavs. However, this proper name became more prominent in the history, the country was called by its inhabitants "Русская Земля", which can be translated as "Russian Land" or "Land of Rus'". In order to distinguish this state from other states derived from it, it is denoted as Kievan Rus' by modern historiography.
The name Rus itself comes from the early medieval Rus' people, Swedish merchants and warriors who relocated from across the Baltic Sea and founded a state centered on Novgorod that became Kievan Rus. An old Latin version of the name Rus' was Ruthenia applied to the western and southern regions of Rus' that were adjacent to Catholic Europe; the current name of the country, Россия, comes from the Byzantine Greek designation of the Rus', Ρωσσία Rossía—spelled Ρωσία in Modern Greek. The standard way to refer to citizens of Russia is rossiyane in Russian. There are two Russian words which are commonly
Luhansk Oblast is the easternmost oblast of Ukraine. Its administrative center is Luhansk; the oblast was established in 1938 and bore the name Voroshilovgrad Oblast in honor of Kliment Voroshilov. Its population is 2,239,500. Important cities within the oblast include Alchevsk, Brianka, Krasnyi Luch, Lysychansk, Pervomaisk, Rubizhne, Sievierodonetsk, Stakhanov; the War in Donbass caused the administrative center of the oblast to be relocated to Sievierodonetsk. Luhansk Oblast is located in eastern Ukraine; the area of the oblast, comprises about 4.42% of the total area of the country. Its longitude from north to south is 250 km, from east to west – 190 km; the oblast has the longest segment of the Ukrainian international border with Russia among other regions consisting of 746 km. It borders the Belgorod and Voronezh Oblasts of Russia on the north, while the Rostov Oblast is located to the east and the south. Among Ukrainian regions, the oblast borders the Donetsk Oblasts to its west; the region is located in the valley of Siversky Donets which splits the region in half.
The southern portion of the region is elevated by the Donetsk Ridge, located closer to the southern border. The highest point is Mohyla Mechetna, the highest point of Donetsk Ridge; the left bank of Siversky Donets is part of the Starobilsk Plain which to the north transforms into the Central Russian Upland. The oblast originated in 1938 as Voroshylovhrad Oblast after the Donetsk Oblast was split between Voroshylovhrad and Stalino oblasts. After the invasion by Nazi Germany in 1941 the region came under a German military administration, due to its proximity to frontlines, it was occupied at the end of 1942 as part of Case Blue German offensive directed towards Stalingrad. However soon after the battle of Stalingrad, in the spring of 1943 Luhansk region once again became center of military operations during the Soviet counter-offensive operation Little Saturn. By the summer of 1943 the region was liberated from the Nazi Germany Armed Forces. During the Soviet times the Oblast bore its current name between 1958 and 1970.
During the fateful March Referendum of 1991, 70.16% of all Ukrainians voted to remain a part of the Soviet Union as a sovereign republic, while only 27.99% voted'no'. In the December 1991 referendum, 83.86% of votes in the oblast were in favor of the Declaration of Independence of Ukraine. In 1994 a referendum took place in the Donetsk Oblast and the Luhansk Oblast, with around 90% supporting the Russian language gaining status of an official language alongside Ukrainian, for the Russian language to be an official language on a regional level. On April 8, 2014, following the annexation of Crimea by Russia, pro-Russian separatists occupying the Luhansk Oblast administrative building planned to declare the independence of the region as the Luhansk Parliamentary Republic, after other pro-Russian separatists declared Donetsk People's Republic in the Donetsk Oblast; when the Luhansk Parliamentary Republic ceased to exist, the separatists declared the Luhansk People's Republic and held a disputed referendum on separating from Ukraine on May 11, 2014.
The legitimacy of the referendums was not recognized by any government. Ukraine does not recognize the referendum, while the US said the polls were illegal. Subsequently, the War in Donbass started; as a result of the War in Donbass, Luhansk insurgents control the southern third of the oblast, which includes the city of Luhansk, the region's most populous city as well as the capital of the oblast. Due to this, most oblast government functions have moved to Severodonetsk, which forces of the Government of Ukraine recaptured in July 2014. Many universities located in the occupied areas have moved to government-controlled cities such as Severodonetsk, Starobelsk or Rubizhne. A survey conducted in December 2014 by the Kyiv International Institute of Sociology found 5.7% of the oblast's population supported their region joining Russia, 84.1% did not support the idea, the rest were undecided or did not respond. Like the rest of the provinces in Ukraine, Luhansk Oblast has double jurisdiction; the oblast is predominantly administrated by the Luhansk Oblast State Administration headed by the governor of the oblast and appointed by the President of Ukraine.
The province has a representative body, the provincial council, headed by its chairman and elected by popular vote. The province is divided into 18 raions, 37 cities, including 14 cities of regional significance; the administrative center is Luhansk. These are listed below with their populations; the province's secondary division consists of various municipalities. Those municipalities may consist of one or more populated places; the municipalities are administratively subordinate to the raion in which they are located, with the exception of 14 cities subordinated directly to the oblast. In addition, the city of Luhansk is subdivided into its own four city-districts. All subdivisions are governed by their respective councils; the population is Russian-speaking, although ethnic Ukrainians constitute a majority. Among
Battle of Rostov (1941)
The Battle of Rostov was a battle of the Eastern Front of World War II, fought around Rostov-on-Don between the Army Group South of Nazi Germany and the Southern Front of the Soviet Union. The battle comprised three phases: the German Sea of Azov Offensive Operation by Army Group South, the Soviet Rostov Defensive Operation by the Southern Front, the Rostov Offensive Operation executed by the same Soviet Front. After forcing their way across the Mius river on 17 November, the German forces captured 10,000 Soviet troops and took Rostov on 21 November. Six days the Southern Front, reinforced with the newly raised 37th Army, counterattacked from the north and threatened to surround the overstretched German III Motorized Army Corps. Rundstedt ordered a retreat to the Mius line from Rostov to prevent the encirclement, which prompted Hitler to fire him. Rundstedt's successor Walther von Reichenau confirmed the retreat order with the backing of the Army High Command Chief of Staff Franz Halder and Hitler relented.
The Red Army retook Rostov on 28 November. It was the first successful major Soviet counteroffensive of the war. After concluding the Battle of Kiev in September 1941, the German Army Group South advanced from the Dniepr River to the Sea of Azov coast. Walther von Reichenau's 6th Army captured Kharkov in the First Battle of Kharkov. Carl-Heinrich von Stülpnagel's 17th Army advanced through Poltava towards Voroshilovgrad. Erich von Manstein's 11th Army moved into the Crimean Peninsula and took control of all of the peninsula by autumn. Ewald von Kleist's 1st Panzer Army advanced from Kiev, encircled Soviet troops at Melitopol in October attacked east along the shore of the Sea of Azov toward Rostov at the mouth of the Don river, known as the gateway to the Caucasus. Rostov was assigned as the objective for the 11th Army now commanded by General Eugen Ritter von Schobert, however he died in a crash on the same day after landing his liaison aircraft in a minefield. To replace him, Manstein was ordered to travel from the Leningrad sector of the front to the extreme southern sector.
He would receive support from the 4th Luftwaffe Air Fleet. At this time the LIVth Army Corps of the 11th Army was still engaged in Crimea, because the Romanian forces were still engaged in the Siege of Odessa, the Army's resources for the Rostov objective were limited against retreating Red Army troops. Therefore, Manstein replaced the LIV Corps with the smaller XXXth Army Corps and XLIXth Mountain Corps and ordered the LIV Corps into the first echelon in the advance to Rostov. Late in September, the Romanian 3rd Army joined the 11th Army in its advance towards Rostov, but was depleted by the attacks of the Soviet 9th and 18th Armies on 26 September; this forced a halt to the Army's advance to safeguard its flank and forced Manstein to use his only mobile reserve unit, the Leibstandarte Brigade to shore up Romanian defenses. The Soviet counter-attack delivered as part of the general Donbass-Rostov Strategic Defensive Operation forced Rundstedt's Army Group South to order his 1st Panzer Army to manoeuvre in order to be better placed to counter any further Soviet thrusts in the Romanian sector of the front, to attempt an encirclement of the two Soviet Armies, successful in the area of Chernigovka where on 8 October the commander of the 18th Soviet Army, General-Lieutenant A.
K. Smirnov, was killed by artillery fire on his command post in the village of Popovka during the breakout attempt between 5 and 10 October 1941; this was interpreted by Hitler as such a success that he declared "The battle of the Sea of Azov is over" on 11 October before the troops had reached their objective. As a commemorative gesture, Hitler issued the order to redesignate the Leibstandarte Brigade as SS Division Leibstandarte; the German 11th Army was ordered back to Crimea to effect the breakthrough of the Isthmus of Perekop. Perceiving that the way to Rostov and the Caucasus was open, Hitler issued an order transferring the objective from the 11th Army to the 1st Panzer Army and attaching to it ill-prepared Romanian 3rd Army, the Italian Alpine Corps, the Slovakian Motorised Brigade. During the subsequent reorganisation of Axis forces the III Panzer Corps and XIV Panzer Corps took the lead, supported by the XLIX Mountain Corps arrived from Crimea. By 17 October 1941 the Mius River was crossed by the 14th Panzer Division and Taganrog was captured by German troops, with the mountain troops entering Stalino, forcing the newly formed 12th Army into a renewed withdrawal.
However, the autumn rains had begun, the Rasputitsa had set in slowing the 1st Panzer Army's advance to "meter by meter". This meant that the leading German units did not reach the outskirts of Rostov until mid-November, having lost contact with the Red Army in the meantime; the assault on Rostov began on 17 November, on 21 November the Germans took Rostov. However, the German lines were over-extended, Kleist's warnings that his left flank was vulnerable and that his tanks were ineffective in the freezing weather were ignored. On 27 November the 37th Army, commanded by Lieutenant-General Anton Ivanovich Lopatin, as part of the Rostov Strategic Offensive Operation, counter-attacked the 1st Panzer Army's spearhead from the north, forcing them to pull out of the city. Adolf Hitler countermanded the retreat; when Rundstedt refused to obey, Hitler sacked him, replaced him with Reichenau. However, Reichenau saw at o
A river is a natural flowing watercourse freshwater, flowing towards an ocean, lake or another river. In some cases a river flows into the ground and becomes dry at the end of its course without reaching another body of water. Small rivers can be referred to using names such as stream, brook and rill. There are no official definitions for the generic term river as applied to geographic features, although in some countries or communities a stream is defined by its size. Many names for small rivers are specific to geographic location. Sometimes a river is defined as being larger than a creek, but not always: the language is vague. Rivers are part of the hydrological cycle. Potamology is the scientific study of rivers, while limnology is the study of inland waters in general. Most of the major cities of the world are situated on the banks of rivers, as they are, or were, used as a source of water, for obtaining food, for transport, as borders, as a defensive measure, as a source of hydropower to drive machinery, for bathing, as a means of disposing of waste.
A river begins at a source, follows a path called a course, ends at a mouth or mouths. The water in a river is confined to a channel, made up of a stream bed between banks. In larger rivers there is also a wider floodplain shaped by flood-waters over-topping the channel. Floodplains may be wide in relation to the size of the river channel; this distinction between river channel and floodplain can be blurred in urban areas where the floodplain of a river channel can become developed by housing and industry. Rivers can flow down mountains, through valleys or along plains, can create canyons or gorges; the term upriver refers to the direction towards the source of the river, i.e. against the direction of flow. The term downriver describes the direction towards the mouth of the river, in which the current flows; the term left bank refers to the left bank in the direction of right bank to the right. The river channel contains a single stream of water, but some rivers flow as several interconnecting streams of water, producing a braided river.
Extensive braided rivers are now found in only a few regions worldwide, such as the South Island of New Zealand. They occur on peneplains and some of the larger river deltas. Anastamosing rivers are quite rare, they have multiple sinuous channels carrying large volumes of sediment. There are rare cases of river bifurcation in which a river divides and the resultant flows ending in different seas. An example is the bifurcation of Nerodime River in Kosovo. A river flowing in its channel is a source of energy which acts on the river channel to change its shape and form. In 1757, the German hydrologist Albert Brahms empirically observed that the submerged weight of objects that may be carried away by a river is proportional to the sixth power of the river flow speed; this formulation is sometimes called Airy's law. Thus, if the speed of flow is doubled, the flow would dislodge objects with 64 times as much submerged weight. In mountainous torrential zones this can be seen as erosion channels through hard rocks and the creation of sands and gravels from the destruction of larger rocks.
A river valley, created from a U-shaped glaciated valley, can easily be identified by the V-shaped channel that it has carved. In the middle reaches where a river flows over flatter land, meanders may form through erosion of the river banks and deposition on the inside of bends. Sometimes the river will cut off a loop, shortening the channel and forming an oxbow lake or billabong. Rivers that carry large amounts of sediment may develop conspicuous deltas at their mouths. Rivers whose mouths are in saline tidal waters may form estuaries. Throughout the course of the river, the total volume of water transported downstream will be a combination of the free water flow together with a substantial volume flowing through sub-surface rocks and gravels that underlie the river and its floodplain. For many rivers in large valleys, this unseen component of flow may exceed the visible flow. Most but not all rivers flow on the surface. Subterranean rivers flow underground in caverns; such rivers are found in regions with limestone geologic formations.
Subglacial streams are the braided rivers that flow at the beds of glaciers and ice sheets, permitting meltwater to be discharged at the front of the glacier. Because of the gradient in pressure due to the overlying weight of the glacier, such streams can flow uphill. An intermittent river only flows and can be dry for several years at a time; these rivers are found in regions with limited or variable rainfall, or can occur because of geologic conditions such as a permeable river bed. Some ephemeral rivers flow during the summer months but not in the winter; such rivers are fed from chalk aquifers which recharge from winter rainfall. In England these rivers are called bournes and give their name to places such as Bournemouth and Eastbourne. In humid regions, the location where flow begins in the smallest tributary streams moves upstream in response to precipitation and downstream in its absence or when active summer vegetation diverts water for evapotrans