Drainage divide in the context of Stream capture

Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east. Europe shares the landmass of Eurasia with Asia, and of Afro-Eurasia with both Africa and Asia. Europe is commonly considered to be separated from Asia by the watershed of the Ural Mountains, the Ural River, the Caspian Sea, the Greater Caucasus, the Black Sea, and the Turkish straits.

Europe covers approx. 10,186,000 square kilometres (3,933,000 sq mi), or 2% of Earth's surface (6.8% of Earth's land area), making it the second-smallest continent (using the seven-continent model). Politically, Europe is divided into about fifty sovereign states, of which Russia is the largest and most populous, spanning 39% of the continent and comprising 15% of its population. Europe had a total population of about 745 million (about 10% of the world population) in 2021; the third-largest after Asia and Africa. The European climate is affected by warm Atlantic currents, such as the Gulf Stream, which produce a temperate climate, tempering winters and summers, on much of the continent. Further from the sea, seasonal differences are more noticeable producing more continental climates.

A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, the drainage divide, made up of a succession of elevated features, such as ridges and hills. A basin may consist of smaller basins that merge at river confluences, forming a hierarchical pattern.

Other terms for a drainage basin are catchment area, catchment basin, drainage area, river basin, water catchment, water basin, and impluvium. In North America, they are commonly called a watershed, though in other English-speaking places, "watershed" is used only in its original sense, that of the drainage divide line.

A river is a natural stream of fresh water that flows on land or inside caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of its course if it runs out of water, or only flow during certain seasons. Rivers are regulated by the water cycle, the processes by which water moves around the Earth. Water first enters rivers through precipitation, whether from rainfall, the runoff of water down a slope, the melting of glaciers or snow, or seepage from aquifers beneath the surface of the Earth.

Rivers flow in channeled watercourses and merge in confluences to form drainage basins, areas where surface water eventually flows to a common outlet. Drainage divides keep rivers separated from other courses of water and causes upstream water within the confines of the divide to fall into the downhill stream. Rivers have a great effect on the landscape around them. They may regularly overflow their banks and flood the surrounding area, spreading nutrients to the surrounding area. Sediment or alluvium carried by rivers shapes the landscape around it, forming deltas and islands where the flow slows down. Rivers rarely run in a straight line, instead, they bend or meander; the locations of a river's banks can change frequently. Rivers get their alluvium from erosion, which carves rock into canyons and valleys.

Montferrat (UK: /ˌmɒntfəˈræt/ MONT-fə-RAT, US: /-ˈrɑːt/ -⁠RAHT; Italian: Monferrato [moɱferˈraːto]; Piedmontese: Monfrà, locally [mʊŋˈfrɒ]; Latin: Mons Ferratus) is a historical region of Piedmont, in northern Italy. It comprises roughly (and its extent has varied over time) the modern provinces of Alessandria and Asti. Montferrat is one of the most important wine districts of Italy. It also has a strong literary tradition, including the 18th-century Asti-born poet and dramatist Vittorio Alfieri and the Alessandrian Umberto Eco.

The territory is cut in two by the river Tanaro. The northern part (the Basso Monferrato, "Low Montferrat"), which lies between that river and the Po, is an area of rolling hills and plains. The southern part (the Alto Monferrato, "High Montferrat") rises from the banks of the Tanaro into the mountains of the Apennines and the water divide between Piedmont and Liguria.

Bugulma-Belebey Upland (Russian: Бугульминско-Белебеевская возвышенность; Bashkir: Бөгөлмә-Бәләбәй ҡалҡыулығы; Tatar: Бөгелмә-Бәләбәй калкулыгы) is an upland in the eastern part of Eastern European Plain, west of the Urals, in Tatarstan, Bashkortostan and Orenburg Oblast, Russia. It forms the drainage divide of the Volga, Kama and Belaya rivers. The upper point of the upland is 418 m height. Romashkino field is placed there.

Likhi Range (Georgian: ლიხის ქედი, romanized: likhis kedi) or Surami Range (Georgian: სურამის ქედი, romanized: suramis kedi) is a mountain range in Georgia, a part of the Caucasus Mountains. It connects the Greater Caucasus and Lesser Caucasus ranges and belongs to the Dzirulula denudative Plateau. It is watershed of the Black and Caspian seas basins and divides the country climatically and geomorphologically.

The highest point in the range is the Ribisa mountain, at 2,470 m (8,100 ft) above sea level. The lowest and most important mountain pass is the Surami Pass at an elevation of 949 m (3,114 ft) which links eastern and western Georgia. A railroad (in the tunnel) runs through the pass, as well as the Zestaponi-Khashuri highway. A southern portion of the Likhi range was historically known as Ghado.

The Afghanistan–China border is a 92-kilometre-long (57 mi) boundary between Afghanistan and China, beginning at the tripoint of both countries with the Pakistan's federally administered territory of Gilgit-Baltistan, following the watershed along the Mustagh Range, and ending at the tripoint with Tajikistan. This short border is in the far northeast of Afghanistan, distant from much of the country or urban areas in either country, at the end of the long, narrow Wakhan Corridor. The Chinese side of the border is in the Chalachigu Valley. The border is crossed by several mountain passes, including Wakhjir Pass in the south and Tegermansu Pass in the north.

Both sides of the border are protected areas: Wakhan National Park in Wakhan District, Badakhshan Province on the Afghan side and Taxkorgan Nature Reserve in Taxkorgan Tajik Autonomous County, Kashgar Prefecture, Xinjiang Uygur Autonomous Region on the Chinese side.

A triple divide or triple watershed is a point on Earth's surface where three drainage basins meet. A triple divide results from the intersection of two drainage divides. Triple divides range from prominent mountain peaks to minor side peaks, down to simple slope changes on a ridge which are otherwise unremarkable. The elevation of a triple divide can be thousands of meters to barely above sea level. Triple divides are a common hydrographic feature of any terrain that has rivers, streams and/or lakes.

Topographic triple divides do not necessarily respect the underground path of water. Thus, depending on the infiltration and the different geological layers, the hydrologic triple divide is often offset from the topographic triple divide.

A continental divide is a drainage divide on a continent such that the drainage basin on one side of the divide feeds into one ocean or sea, and the basin on the other side either feeds into a different ocean or sea, or else is endorheic, not connected to the open sea. Every continent on Earth except Antarctica (which has no known significant, definable free-flowing surface rivers) has at least one continental drainage divide; islands, even small ones like Killiniq Island on the Labrador Sea in Canada, may also host part of a continental divide or have their own island-spanning divide.The endpoints of a continental divide may be coastlines of gulfs, seas or oceans, the boundary of an endorheic basin, or another continental divide. One case, the Great Basin Divide, is a closed loop around an endorheic basin. The endpoints where a continental divide meets the coast are not always definite since the exact border between adjacent bodies of water is usually not clearly defined. The International Hydrographic Organization's publication Limits of Oceans and Seas defines exact boundaries of oceans, but it is not universally recognized. Where a continental divide meets an endorheic basin, such as the Great Divide Basin of Wyoming, the continental divide splits and encircles the basin. Where two divides intersect, they form a triple divide, or a tripoint, a junction where three watersheds meet.

Whether a divide is considered a continental divide distinguished from other secondary drainage divides may depend on whether the associated gulfs, seas, or oceans are considered separate. For example, the Gulf of Mexico is considered separate from the Atlantic Ocean, so the Eastern Continental Divide separates their respective watersheds. But the Sea of Cortez is usually not considered separate from the Pacific Ocean, so the divide between the Colorado River watershed, which drains to the Sea of Cortez, and the Columbia River watershed, which drains to the Pacific Ocean, is not considered to be a continental divide.

The trade route from the Varangians to the Greeks was a medieval trade route that connected Scandinavia, Kievan Rus' and the Eastern Roman Empire. The route allowed merchants along its length to establish a direct prosperous trade with the Empire, and prompted some of them to settle in the territories of present-day Belarus, Russia and Ukraine. The majority of the route comprised a long-distance waterway, including the Baltic Sea, several rivers flowing into the Baltic Sea, and rivers of the Dnieper river system, with portages on the drainage divides. An alternative route was along the Dniester river with stops on the western shore of Black Sea. These more specific sub-routes are sometimes referred to as the Dnieper trade route and Dniester trade route, respectively.

The route began in Scandinavian trading centers such as Birka, Hedeby, and Gotland, the eastern route crossed the Baltic Sea, entered the Gulf of Finland, and followed the Neva River into Lake Ladoga. Then it followed the Volkhov River upstream past the towns of Staraya Ladoga and Novgorod (where it met the Volga trade route and which became a major trade centre), crossed Lake Ilmen, and continued up the Lovat River, the Kunya River and possibly the Serezha River [ru]. From there, a portage led to the Toropa River [ru] and downstream to the Western Dvina River. From the Western Dvina, the ships went upstream along the Kasplya River and were portaged again to the Katynka River (near Katyn), a tributary of the Dnieper. It seems probable that once the route was established, the goods were unloaded onto land transport to cross the portage and reloaded onto other waiting ships on the Dnieper. Along the Dnieper, the route crossed several major rapids and passed through Kiev. After entering the Black Sea, it followed its west coast to Constantinople.

Mont Blanc (UK: /ˌmɒ̃ˈblɒ̃(k)/, US: /ˌmɒn(t)ˈblɑːŋk/) is a mountain in the Alps, rising 4,805.59 m (15,766 ft) above sea level, located right at the Franco-Italian border. It is the highest mountain in Europe outside the Caucasus Mountains, the second-most prominent mountain in Europe (after Mount Elbrus in Russia), and the 11th most prominent mountain in the world.

The mountain gives its name to its range, the Mont Blanc massif, which straddles parts of France, Italy, and Switzerland. Mont Blanc's summit lies on the watershed line between the valleys of Ferret and Veny in Italy, and the valleys of Montjoie, and Arve in France. Ownership of the summit area has long been disputed between France and Italy.

The Siachen Glacier is a glacier located in the eastern Karakoram range of the Himalayas, just northeast of the point NJ9842 where the Line of Control between India and Pakistan ends in northeastern Kashmir. At 76 km (47 mi) long, it is the longest glacier in the Karakoram and second-longest in the world's non-polar areas. It falls from an altitude of 5,753 m (18,875 ft) above sea level at its head at Indira Col on the India–China border down to 3,620 m (11,875 ft) at its terminus. The entire Siachen Glacier, with all major passes, has been under the administration of India as part of the union territory of Ladakh since 1984. Pakistan maintains a territorial claim over the Siachen Glacier and controls the region west of Saltoro Ridge, lying west of the glacier, with Pakistani posts located 1 km below more than 100 Indian posts on the ridge.

The Siachen Glacier lies immediately south of the great drainage divide that separates the Eurasian Plate from the Indian subcontinent in the extensively glaciated portion of the Karakoram sometimes called the "Third Pole". The glacier lies between the Saltoro Ridge immediately to the west and the main Karakoram range to the east. The Saltoro Ridge originates in the north from the Sia Kangri peak on the China border in the Karakoram range. The crest of the Saltoro Ridge's altitudes range from 5,450 to 7,720 m (17,880 to 25,330 feet). The major passes on this ridge are, from north to south, Sia La at 5,589 m (18,336 ft), Bilafond La at 5,450 m (17,880 ft), and Gyong La at 5,689 m (18,665 ft). The average winter snowfall is more than 1000 cm (35 ft) and temperatures can dip to −50 °C (−58 °F). Including all tributary glaciers, the Siachen Glacier system covers about 700 km (270 sq mi).

The New York–New Jersey Harbor Estuary, also known as the Hudson-Raritan Estuary, is in the northeastern states of New Jersey and New York on the East Coast of the United States. The system of waterways of the Port of New York and New Jersey forms one of the most intricate natural harbors in the world and one of the busiest ports of the United States. The harbor opens onto the New York Bight in the Atlantic Ocean to the southeast and Long Island Sound to the northeast.

Although the overall form of the estuary remains unchanged from the time of Giovanni da Verrazzano's visit in 1524, all parts have changed at least a little, and some parts, such as Hell Gate and Ellis Island, have been almost completely altered. In the greatest hidden change, the navigational channels have been deepened from the natural 17 feet (5.2 m) depth to 45 feet (14 m). In some places this required blasting of bedrock.

The Mont Blanc massif (French: Massif du Mont-Blanc [masif dy mɔ̃ blɑ̃]; Italian: Massiccio del Monte Bianco) is a mountain range in the Alps, located mostly in France and Italy, but also straddling Switzerland at its northeastern end. It contains eleven major independent summits, each over 4,000 metres (13,123 ft) in height. It is named after Mont Blanc (4,808 metres (15,774 ft)), the highest point in western Europe and the European Union. Because of its considerable overall altitude, a large proportion of the massif is covered by glaciers, which include the Mer de Glace and the Miage Glacier – the longest glaciers in France and Italy, respectively.

The massif forms a watershed between the vast catchments of the rivers Rhône and Po, and a tripoint between France, Italy and Switzerland; it also marks the border between two climate regions by separating the northern and western Alps from the southern Alps. The mountains of the massif consist mostly of granite and gneiss rocks and at high altitudes the vegetation is an arctic-alpine flora.