The Himalayas form a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has many of the Earth’s highest peaks, including the highest, Mount Everest. The Himalayas include over fifty mountains exceeding 7,200 m (23,600 ft) in elevation, including ten of the fourteen 8,000-metrepeaks. By contrast, the highest peak outside Asia (Aconcagua, in the Andes) is 6,961 m (22,838 ft) tall Lifted by the subduction of the Indian tectonic plate under the Eurasian Plate, the Himalayan mountain range runs west-northwest to east-southeast in an arc 2,400 km (1,500 mi) long. Its western anchor, Nanga Parbat, lies just south of the northernmost bend of Indus river. Its eastern anchor, Namcha Barwa, is just west of the great bend of the Yarlung Tsangpo River (upper stream of the Brahmaputra River). The Himalayan range is bordered on the northwest by the Karakoram and the Hindu Kush ranges. To the north, the chain is separated from the Tibetan Plateau by a 50–60 km (31–37 mi) wide tectonic valley called the Indus-Tsangpo Suture. Towards the south the arc of the Himalaya is ringed by the very low Indo-Gangetic Plain. The range varies in width from 350 km (220 mi) in the west (Pakistan) to 150 km (93 mi) in the east (Arunachal Pradesh). The Himalayas are distinct from the other great ranges of central Asia, although sometimes the term ‘Himalaya’ (or ‘Greater Himalaya’) is loosely used to include the Karakoram and some of the other ranges.
The Alps are the highest and most extensive mountain range system that lies entirely in Europe, separating Southern from Central and Western Europe and stretching approximately 1,200 kilometres (750 mi) across eight Alpine countries (from west to east): France, Switzerland, Italy, Monaco, Liechtenstein, Austria, Germany, and Slovenia. The mountains were formed over tens of millions of years as the African and Eurasian tectonic plates collided. Extreme shortening caused by the event resulted in marine sedimentary rocks rising by thrusting and folding into high mountain peaks such as Mont Blanc and the Matterhorn. Mont Blanc spans the French–Italian border, and at 4,810 m (15,781 ft) is the highest mountain in the Alps. The Alpine region area contains about a hundred peaks higher than 4,000 metres (13,000 ft).The altitude and size of the range affects the climate in Europe; in the mountains precipitation levels vary greatly and climatic conditions consist of distinct zones. Wildlife such as ibex live in the higher peaks to elevations of 3,400 m (11,155 ft), and plants such as Edelweiss grow in rocky areas in lower elevations as well as in higher elevations. Evidence of human habitation in the Alps goes back to the Paleolithic era. A mummified man, determined to be 5,000 years old, was discovered on a glacier at the Austrian–Italian border in 1991.
Mariana Trench, also called Marianas Trench, deep-sea trench in the floor of the western North Pacific Ocean, the deepest such trench known on Earth, located mostly east as well as south of the Mariana Islands. It is part of the western Pacific system of oceanic trenches coinciding with subduction zones—points where two adjacent tectonic plates collide, one being forced below the other. An arcing depression, the Mariana Trench stretches for more than 1,580 miles (2,540 km) with a mean width of 43 miles (69 km). The greatest depths are reached in Challenger Deep, a smaller steep-walled valley on the floor of the main trench southwest of Guam. The Mariana Trench, which is situated within the territories of the U.S. dependencies of the Northern Mariana Islands and Guam, was designated a U.S. national monument in 2009. The first attempt to measure the depth of the trench was made in 1875 during the Challenger Expedition (1872–76), when a sounding of 26,850 feet (8,184 metres) was obtained near the southern end of the trench. In 1899 Nero Deep (31,693 feet [9,660 metres]) was discovered southeast of Guam. That sounding was not exceeded until a 32,197-foot (9,813-metre) hole was found in the vicinity 30 years later. In 1957, during the International Geophysical Year, the Soviet research ship Vityaz sounded a new world record depth of 36,056 feet (10,990 metres) in Challenger Deep. That value was later increased to 36,201 feet (11,034 metres). Since then several measurements of the Challenger Deep have been made, using increasingly sophisticated electronic equipment.
The Bermuda Triangle
The Bermuda Triangle, also known as the Devil’s Triangle or Hurricane Alley, is a loosely-defined region in the western part of the North Atlantic Ocean, where a number of aircraft and ships are said to have disappeared under mysterious circumstances. Most reputable sources dismiss the idea that there is any mystery. The vicinity of the Bermuda Triangle is amongst the most heavily traveled shipping lanes in the world, with ships frequently crossing through it for ports in the Americas, Europe and the Caribbean islands. Cruise ships and pleasure craft regularly sail through the region, and commercial and private aircraft routinely fly over it. Popular culture has attributed various disappearances to the paranormal or activity by extraterrestrial beings. Documented evidence indicates that a significant percentage of the incidents were spurious, inaccurately reported, or embellished by later authors. The earliest suggestion of unusual disappearances in the Bermuda area appeared in a September 17, 1950, article published in The Miami Herald (Associated Press) by Edward Van Winkle Jones. Two years later, Fate magazine published “Sea Mystery at Our Back Door”, a short article by George X. Sand covering the loss of several planes and ships, including the loss of Flight 19, a group of five US Navy Grumman TBM Avenger torpedo bombers on a training mission.
The Gobi Desert
The Gobi Desert is a large desert or brushland region in Asia. It covers parts of Northern and Northeastern China, and of southern Mongolia. The desert basins of the Gobi are bounded by the Altai Mountains and the grasslands and steppes of Mongolia on the north, by the Taklamakan Desert to the west, by the Hexi Corridor and Tibetan Plateau to the southwest, and by the North China Plain to the southeast. The Gobi is notable in history as part of the great Mongol Empire, and as the location of several important cities along the Silk Road.The Gobi is a rain shadow desert, formed by the Tibetan Plateau blocking precipitation from the Indian Ocean reaching the Gobi territory.
The Sahara Desert
The Sahara or ‘the Great Desert’) is a desert located on the African continent. It is the largest hot desert in the world, and the third largest desert overall after Antarctica and the Arctic.Its area of 9,200,000 square kilometres (3,600,000 sq mi) is comparable to the area of China or the United States.The name ‘Sahara’ is derived from a dialectal Arabic word for “desert”, ṣaḥra. The desert comprises much of North Africa, excluding the fertile region on the Mediterranean Sea coast, the Atlas Mountains of the Maghreb, and the Nile Valley in Egypt and Sudan. It stretches from the Red Sea in the east and the Mediterranean in the north to the Atlantic Ocean in the west, where the landscape gradually changes from desert to coastal plains. To the south, it is bounded by the Sahel, a belt of semi-arid tropical savanna around the Niger River valley and the Sudan Region of Sub-Saharan Africa. The Sahara can be divided into several regions including: the western Sahara, the central Ahaggar Mountains, the Tibesti Mountains, the Aïr Mountains, the Ténéré desert, and the Libyan Desert.
The Kalahari Desert
The Kalahari Desert is a large semi-arid sandy savanna in Southern Africa extending for 900,000 square kilometres (350,000 sq mi), covering much of Botswana, parts of Namibia and regions of South Africa. It is not to be confused with the Angolan, Namibian and S. African Namib coastal desert, whose name is of Khoekhoegowa borigin and means “vast place”. Drainage of the desert is by dry valleys, seasonally inundated pans and the large salt pans of the Makgadikgadi Pan in Botswana and Etosha Pan in Namibia. The only permanent river, the Okavango, flows into a delta in the northwest, forming marshes that are rich in wildlife. Ancient dry riverbeds—called omuramba—traverse the central northern reaches of the Kalahari and provide standing pools of water during the rainy season. A semi-desert, with huge tracts of excellent grazing after good rains, the Kalahari supports more animals and plants than a true desert, such as the Namib Desert to the west. There are small amounts of rainfall and the summer temperature is very high. The driest areas usually receive 110–200 millimetres (4.3–7.9 in) of rain per year, and the wettest just a little over 500 millimetres (20 in). The surrounding Kalahari Basin covers over 2,500,000 square kilometres (970,000 sq mi) extending further into Botswana, Namibia and South Africa, and encroaching into parts of Angola, Zambia and Zimbabwe. Numerous pans exist within the Kalahari, including the Groot-vloer Pan and Verneukpan where evidence of a wetter climate exists in the form of former contouring for capturing of water. This and other pans, as well as river bottoms, were written about extensively at Sciforums by an article by Walter Wagner regarding the extensive formerly wet areas of the Kalahari. The Kalahari is extensive and extends further north where abandoned extensive roadways also exist
The Thar Desert
The Thar Desert, also known as the Great Indian Desert, is a large arid region in the northwestern part of the Indian subcontinent that covers an area of 200,000 km2 (77,000 sq mi) and forms a natural boundary between India and Pakistan. It is the world’s 17th largest desert, and the world’s 9th largest subtropical desert. About 85% of the Thar Desert is located within India, with the remaining 15% in Pakistan. In India, it covers about 170,000 km2 (66,000 sq mi), and the remaining 30,000 km2 (12,000 sq mi) of the desert is within Pakistan. The Thar desert forms approximately 5%(~4.56%) of the total geographic area of India. More than 60% of the desert lies in the state of Rajasthan, and extends into Gujarat, Punjab, and Haryana.The desert comprises a very dry part, the Marusthali region in the west, and a semidesert region in the east with fewer sand dunes and slightly more precipitation.
The Arabian Desert is a vast desert wilderness in Western Asia. It stretches from Yemen to the Persian Gulf and Oman to Jordan and Iraq. It occupies most of the Arabian Peninsula, with an area of 2,330,000 square kilometers (900,000 sq mi). It is the fifth largest desert in the world, and the largest in Asia. At its center is Ar-Rub’al-Khali (The Empty Quarter), one of the largest continuous bodies of sand in the world.Gazelles, oryx, sand cats, and spiny-tailed lizards are just some of the desert-adapted species that survive in this extreme environment, which features everything from red dunes to deadly quicksand. The climate is mostly dry (the major part receives around 100 mm (3.9 in) of rain per year but some very rare places receives down to 50 mm), and temperatures oscillate between very high heat and seasonal night time freezes. It is part of the deserts and xeric shrublands biome and the Palearctic ecozone.
The Atacama Desert is a desert plateau in South America covering a 1000-km (600-mi) strip of land on the Pacific coast, west of the Andes mountains. The Atacama desert is one of the driest places in the world (the driest being the McMurdo Dry Valleys , as well as the only true desert to receive less precipitation than the polar deserts. According to estimates, the Atacama Desert occupies 105,000 km2 (41,000 sq mi), or 128,000 km2 (49,000 sq mi) if the barren lower slopes of the Andes are included. Most of the desert is composed of stony terrain, salt lakes (salares), sand, and felsic lava that flows towards the Andes. The desert owes its extreme aridity to a constant temperature inversion due to the cool north-flowing Humboldt ocean current, and to the presence of the strong Pacific anticyclone. The most arid region of the Atacama desert is situated between two mountain chains (the Andes and the Chilean Coast Range) of sufficient height to prevent moisture advection from either the Pacific or the Atlantic Oceans, a two-sided rain shadow.
The Sonoran Desert is a North American desert which covers large parts of the Southwestern United States in Arizona and California and of Northwestern Mexico in Sonora, Baja California, and Baja California Sur. It is the hottest desert in Mexico. It has an area of 260,000 square kilometers (100,000 sq mi). The western portion of the United States–Mexico border passes through the Sonoran Desert. The desert contains a variety of unique and endemic plants and animals, such as the saguaro (Carnegiea gigantea) and organ pipe cactus (Stenocereus thurberi).
The Amazon River in South America is the largest river by discharge volume of water in the world, and by some definitions it is the longest. The headwaters of the Apurímac River on Nevado Mismi had been considered for nearly a century as the Amazon’s most distant source, until a 2014 study found it to be the headwaters of the Mantaro River on the Cordillera Rumi Cruz in Peru.The Mantaro and Apurímac join, and with other tributaries form the Ucayali River, which in turn meets the Marañón River upstream of Iquitos, Peru, to form what countries other than Brazil consider to be the main stem of the Amazon. Brazilians call this section the Solimões River above its confluence with the Rio Negro to form what Brazilians call the Amazon at the Meeting of Waters at Manaus, the river’s largest city. At an average discharge of about 209,000 cubic metres per second (7,400,000 cu ft/s; 209,000,000 L/s; 55,000,000 USgal/s)—approximately 6,591 cubic kilometres per annum (1,581 cu mi/a), greater than the next seven largest independent rivers combined—the Amazon represents 20% of the global riverine discharge to the ocean. The Amazon basin is the largest drainage basin in the world, with an area of approximately 7,050,000 square kilometres (2,720,000 sq mi). The Amazon River is disputed longest river in the world (Brazilian government claims it to be longer than the Nile, while every other nation claims that the Nile is the longest River in the world). The portion of the river’s drainage basin in Brazil alone is larger than any other river’s basin. The Amazon enters Brazil with only one-fifth of the flow it finally discharges into the Atlantic Ocean, yet already has a greater flow at this point than the discharge of any other river.
The Brahmaputra is one of the major rivers of Asia, a trans-boundary river which flows through China, India and Bangladesh. As such, it is known by various names in the region such as Brohmoputro noi in Assam, masculine form of the tatsama ‘nodi “river”) Brohmoputro; Brahmaputra in Sanskrit ; and yar klung gtsang po Yarlung Tsangpo in Tibetan language. It is also called Tsangpo-Brahmaputra (when referring to the whole river including the stretch within Tibet). The Manas River, which runs through Bhutan, joins it at Jogighopa, in India. It is the ninth largest river in the world by discharge, and the 15th longest. With its origin in the Manasarovar Lake region, located on the northern side of the Himalayas in Burang County of Tibet as the Yarlung Tsangpo River, it flows across southern Tibet to break through the Himalayas in great gorges (including the Yarlung Tsangpo Grand Canyon) and into Arunachal Pradesh (India). It flows southwest through the Assam Valley as Brahmaputra and south through Bangladesh as the Jamuna (not to be mistaken with Yamuna of India). In the vast Ganges Delta, it merges with the Padma, the popular name of the river Ganges in Bangladesh, and finally the Meghna and from here it is known as Meghna before emptying into the Bay of Bengal. About 2,899.9 km (1,801.9 mi) long, the Brahmaputra is an important river for irrigation and transportation. The basin, especially south of Tibet, is characterized by high levels of rainfall. Kanchenjunga (8,586 m) is the only peak above 8,000 m, hence is the highest point within the Brahmaputra basin.
The Ganges flows through the nations of India and Bangladesh. The 2,525 km (1,569 mi) river rises in the western Himalayas in the Indian state of Uttarakhand, and flows south and east through the Gangetic Plain of North India. After entering West Bengal, it divides into two rivers: the Hooghly and the Padma River. The Hooghly, or Adi Ganga, flows through several districts of West Bengal and into the Bay of Bengal near Sagar Island. The other, the Padma, also flows into and through Bangladesh, and joins the Meghna river which ultimately empties into the Bay of Bengal.
The Ganges is highly polluted. Pollution threatens not only humans, but also more than 140 fish species, 90 amphibian species and the endangered Ganges river dolphin. The Ganges is a major source of global ocean plastic pollution. The levels of fecal coliform bacteria from human waste in the waters of the river near Varanasi are more than 100 times the Indian government’s official limit. The Ganga Action Plan, an environmental initiative to clean up the river, has been a major failure thus far, due to rampant corruption, lack of will on behalf of the government and its bureaucracy, lack of technical expertise, poor environmental planning, and lack of support from religious authorities.
The Indus River
The Indus River (locally called Sindhu) is one of the longest rivers in Asia. Originating in the Tibetan Plateau in the vicinity of Lake Manasarovar, the river runs a course through the Ladakh region of Jammu and Kashmir, India, towards the Gilgit-Baltistan region of Pakistan and the Hindukush ranges, and then flows in a southerly direction along the entire length of Pakistan to merge into the Arabian Sea near the port city of Karachi in Sindh. It is the longest river and national river of Pakistan. The river has a total drainage area exceeding 1,165,000 km2 (450,000 sq mi). Its estimated annual flow stands at around 243 km3(58 cu mi), twice that of the Nile River and three times that of the Tigris and Euphrates rivers combined, making it one of the largest rivers in the world in terms of annual flow. The Zanskar is its left bank tributary in Ladakh. In the plains, its left bank tributary is the Panjnad which itself has five major tributaries, namely, the Chenab, Jhelum, the Ravi, the Beas, and the Sutlej. Its principal right bank tributaries are the Shyok, the Gilgit, the Kabul, the Gomal, and the Kurram. Beginning in a mountain spring and fed with glaciers and rivers in the Himalayas, the river supports ecosystems of temperate forests, plains and arid countryside.
The Yellow River
Yellow River or Huang He is the second longest river in China, after the Yangtze River, and the sixth longest river system in the world at the estimated length of 5,464 km (3,395 mi). Originating in the Bayan Har Mountains in Qinghai province of Western China, it flows through nine provinces, and it empties into the Bohai Sea near the city of Dongying in Shandong province. The Yellow River basin has an east–west extent of about 1,900 kilometers (1,180 mi) and a north–south extent of about 1,100 km (680 mi). Its total drainage area is about 752,546 square kilometers (290,560 sq mi). Its basin was the birthplace of ancient Chinese civilization, and it was the most prosperous region in early Chinese history. There are frequent devastating floods and course changes produced by the continual elevation of the river bed, sometimes above the level of its surrounding farm fields.
The Volga is the longest river in Europe with a catchment area of 1,350,000 square kilometres. It is also Europe’s largest river in terms of discharge and drainage basin. The river flows through central Russia and into the Caspian Sea, and is widely regarded as the national river of Russia.
Eleven of the twenty largest cities of Russia, including the capital, Moscow, are located in the Volga’s drainage basin. Rising in the Valdai Hills 225 meters (738 ft) above sea level northwest of Moscow and about 320 kilometers (200 mi) southeast of Saint Petersburg, the Volga heads east past Lake Sterzh, Tver, Dubna, Rybinsk, Yaroslavl, Nizhny Novgorod, and Kazan. From there it turns south, flows past Ulyanovsk, Tolyatti, Samara, Saratov and Volgograd, and discharges into the Caspian Sea below Astrakhan at 28 meters (92 ft) below sea level. At its most strategic point, it bends toward the Don (“the big bend”). Volgograd, formerly Stalingrad, is located there. The fertile river valley provides large quantities of wheat, and also has many mineral riches. A substantial petroleum industry centers on the Volga valley. Other resources include natural gas, salt, and potash. The Volga Delta and the nearby Caspian Sea offer superb fishing grounds. Astrakhan, at the delta, is the center of the caviar industry.
The Danube River
The Danube is Europe’s second longest river, after the Volga. It is located in Central and Eastern Europe. The Danube was once a long-standing frontier of the Roman Empire, and today flows through 10 countries, more than any other river in the world. Originating in Germany, the Danube flows southeast for 2,850 km (1,770 mi), passing through or bordering Austria, Slovakia, Hungary, Croatia, Serbia, Romania, Bulgaria, Moldova and Ukraine before draining into the Black Sea. Its drainage basin extends into nine more countries. The Danube river basin is home to fish species such as pike, zander, huchen, Wels catfish, burbot and tench. It is also home to a large diversity of carp and sturgeon, as well as salmon and trout. A few species of euryhaline fish, such as European seabass, mullet, and eel, inhabit the Danube Delta and the lower portion of the river. Since ancient times, the Danube has become a traditional trade route in Europe, nowadays 2,415 km (1,501 mi) of its total length being navigable. The river is also an important source of energy and drinking water.
The Rhine is one of the major European rivers, which has its sources in Switzerland and flows in a mostly northerly direction through Germany and The Netherlands, emptying into the North Sea. The river begins in the Swiss canton of Graubünden in the southeastern Swiss Alps, forms part of the Swiss-Liechtenstein, Swiss-Austrian, Swiss-German and then the Franco-German border, then flows through the German Rhineland and the Netherlands and eventually empties into the North Sea. The largest city on the Rhine is Cologne, Germany, with a population of more than 1,050,000 people. It is the second-longest river in Central and Western Europe (after the Danube), at about 1,230 km (760 mi),with an average discharge of about 2,900 m3/s (100,000 cu ft/s). The Rhine and the Danube formed most of the northern inland frontier of the Roman Empire and, since those days, the Rhine has been a vital and navigable waterway carrying trade and goods deep inland. Its importance as a waterway in the Holy Roman Empire is supported by the many castles and fortifications built along it. In the modern era, it has become a symbol of German nationalism.Other important cities on the Rhine are Düsseldorf (Germany), Rotterdam (Netherlands), Strasbourg (France) and Basel (Switzerland).
The Kama is a river 1,805 kilometres (1,122 mi) long in Russia. It is the longest left tributary of the Volga and the largest one in discharge. At their confluence, in fact, the Kama is even larger than the Volga. It starts in the Udmurt Republic, near Kuliga, flowing northwest for 200 kilometres (120 mi), turning northeast near Loyno for another 200 kilometres (120 mi), then turning south and west in Perm Krai, flowing again through the Udmurt Republic and then through the Republic of Tatarstan, where it meets the Volga.
The Moskva River
The Moskva River is a river of western Russia. It rises about 140 km (90 mi) west of Moscow, and flows roughly east through the Smolensk and Moscow Oblasts, passing through central Moscow. About 110 km (70 mi) south east of Moscow, at the city of Kolomna, it flows into the Oka River, itself a tributary of the Volga, which ultimately flows into the Caspian Sea. The river is 503 km (313 mi) long, with a vertical drop of 155 m (509 ft) (long-term average In Moscow, the river freezes occasionally; during an unusually warm winter in 2006–2007, ice began melting on January 25.
The Seine is a 777-kilometre-long (483 mi) river and an important commercial waterway within the Paris Basin in the north of France. It rises at Source-Seine, 30 kilometres (19 mi) northwest of Dijon in northeastern France in the Langres plateau, flowing through Paris and into the English Channel at Le Havre (and Honfleur on the left bank). It is navigable by ocean-going vessels as far as Rouen, 120 kilometres (75 mi) from the sea. Over 60 percent of its length, as far as Burgundy, is negotiable by commercial riverboats, and nearly its whole length is available for recreational boating; excursion boats offer sightseeing tours of the river banks in Paris, lined with top monuments including Notre-Dame, the Eiffel Tower, the Louvre Museum and Musée d’Orsay.
The Tigris is the eastern of the two great rivers that define Mesopotamia, the other being the Euphrates. The river flows south from the mountains of southeastern Turkey through Iraq and empties into the Persian Gulf. The Tigris is 1,750 km long, rising in the Taurus Mountains of eastern Turkey about 25 km southeast of the city of Elazig and about 30 km from the headwaters of the Euphrates. The river then flows for 400 km through Turkish territory before becoming the border between Syria and Turkey. This stretch of 44 km is the only part of the river that is located in Syria. Baghdad, the capital of Iraq, stands on the banks of the Tigris. The port city of Basra straddles the Shatt al-Arab. In ancient times, many of the great cities of Mesopotamia stood on or near the Tigris, drawing water from it to irrigate the civilization of the Sumerians. Notable Tigris-side cities included Nineveh, Ctesiphon, and Seleucia, while the city of Lagash was irrigated by the Tigris via a canal dug around 2900 B.C.
The Potomac River is located within the Mid-Atlantic region of the United States and flows from the Potomac Highlands into the Chesapeake Bay. The river (main stem and North Branch) is approximately 405 miles (652 km) long, with a drainage area of about 14,700 square miles (38,000 km2). In terms of area, this makes the Potomac River the fourth largest river along the Atlantic coast of the United States and the 21st largest in the United States. Over 5 million people live within the Potomac watershed. The river forms part of the borders between Maryland and Washington, D.C., on the left descending bank and West Virginia and Virginia on the river’s right descending bank. The majority of the lower Potomac River is part of Maryland. Exceptions include a small tidal portion within the District of Columbia, and the border with Virginia being delineated from “point to point” (thus various bays and shoreline indentations lie in Virginia). Except for a small portion of its headwaters in West Virginia, the North Branch Potomac River is considered part of Maryland to the low water mark on the opposite bank. The South Branch Potomac River lies completely within the state of West Virginia except for its headwaters, which lie in Virginia.
The Hudson River is a 315-mile (507 km) river that flows from north to south primarily through eastern New York in the United States. The river originates in the Adirondack Mountains of Upstate New York, flows southward through the Hudson Valley to the Upper New York Bay between New York City and Jersey City. It eventually drains into the Atlantic Ocean at New York Harbor. The river serves as a political boundary between the states of New Jersey and New York at its southern end. Further north, it marks local boundaries between several New York counties. The lower half of the river is a tidal estuary, deeper than the body of water into which it flows, occupying the Hudson Fjord, an inlet which formed during the most recent period of North American glaciation, estimated at 26,000 to 13,300 years ago. Tidal waters influence the Hudson’s flow from as far north as the city of Troy. The river is named after Henry Hudson, an Englishman sailing for the Dutch East India Company, who explored it in 1609, and after whom Hudson Bay in Canada is also named.
The Nile is a major north-flowing river in northeastern Africa, and is the longest river in Africa and the disputed longest river in the world (Brazilian government claims that the Amazon River is longer than the Nile). The Nile, which is about 6,650 km (4,130 mi) long, is an “international” river as its drainage basin covers eleven countries, namely, Tanzania, Uganda, Rwanda, Burundi, the Democratic Republic of the Congo, Kenya, Ethiopia, Eritrea, South Sudan, Republic of the Sudan and Egypt. In particular, the Nile is the primary water source of Egypt and Sudan.The river Nile has two major tributaries, the White Nile and Blue Nile. The White Nile is considered to be the headwaters and primary stream of the Nile itself. The Blue Nile, however, is the source of most of the water and silt. The White Nile is longer and rises in the Great Lakes region of central Africa, with the most distant source still undetermined but located in either Rwanda or Burundi. It flows north through Tanzania, Lake Victoria, Uganda and South Sudan. The Blue Nile begins at Lake Tana in Ethiopia and flows into Sudan from the southeast. The two rivers meet just north of the Sudanese capital of Khartoum. The northern section of the river flows north almost entirely through the Sudanese desert to Egypt, then ends in a large delta and flows into the Mediterranean Sea. Egyptian civilization and Sudanese kingdoms have depended on the river since ancient times. Most of the population and cities of Egypt lie along those parts of the Nile valley north of Aswan, and nearly all the cultural and historical sites of Ancient Egypt are found along river banks.
The great Congo River , formerly known as the Zaire River under the Mobutu regime, is the second longest river in Africa, shorter only than the Nile, as well as the second largest river in the world by discharge volume, following only the Amazon. It is also the world’s deepest recorded river, with measured depths in excess of 220 m (720 ft). The Congo-Lualaba-Chambeshi River system has an overall length of 4,700 km (2,920 mi), which makes it the world’s ninth-longest river. The Chambeshi is a tributary of the Lualaba River, and Lualaba is the name of the Congo River upstream of Boyoma Falls, extending for 1,800 km (1,120 mi). Measured along with the Lualaba, the main tributary, the Congo River has a total length of 4,370 km (2,715 mi). It is the only river to cross the equator twice.The Congo Basin has a total area of about 4,000,000 km2 (1,500,000 sq mi), or 13% of the entire African landmass.
The Niger River
The Niger River is the principal river of West Africa, extending about 4,180 km (2,600 mi). Its drainage basin is 2,117,700 km2 (817,600 sq mi) in area. Its source is in the Guinea Highlands in southeastern Guinea. It runs in a crescent through Mali, Niger, on the border with Benin and then through Nigeria, discharging through a massive delta, known as the Niger Delta or the Oil Rivers, into the Gulf of Guinea in the Atlantic Ocean. The Niger is the third-longest river in Africa, exceeded only by the Nile and the Congo River (also known as the Zaïre River). Its main tributary is the Benue River. The Niger River is a relatively “clear” river, carrying only a tenth as much sediment as the Nile because the Niger’s headwaters lie in ancient rocks that provide little silt. Like the Nile, the Niger floods yearly; this begins in September, peaks in November, and finishes by May. The Niger takes one of the most unusual routes of any major river, a boomerang shape that baffled geographers for two centuries. Its source is just 240 km (150 mi) inland from the Atlantic Ocean, but the river runs directly away from the sea into the Sahara Desert, then takes a sharp right turn near the ancient city of Timbuktu (Tombouctou) and heads southeast to the Gulf of Guinea. An unusual feature of the river is the Inner Niger Delta, which forms where its gradient suddenly decreases. The result is a region of braided streams, marshes, and lakes the size of Belgium; the seasonal floods make the Delta extremely productive for both fishing and agriculture.
The Andean Mountains
The Andean Mountains are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. This range is about 7,000 km (4,300 mi) long, about 200 to 700 km (120 to 430 mi) wide (widest between 18° south and 20° south latitude), and of an average height of about 4,000 m (13,000 ft). The Andes extend from north to south through seven South American countries: Venezuela, Colombia, Ecuador, Peru, Bolivia, Chile and Argentina. Along their length, the Andes are split into several ranges, separated by intermediate depressions. The Andes are the location of several high plateaus – some of which host major cities such as Quito, Bogotá, Cali, Arequipa, Medellín, Sucre, Mérida and La Paz. The Altiplano plateau is the world’s second-highest after the Tibetan plateau. These ranges are in turn grouped into three major divisions based on climate: the Tropical Andes, the Dry Andes, and the Wet Andes.The Andes Mountains are the world’s highest mountain range outside Asia. The highest mountain outside Asia, Argentina’s Mount Aconcagua, rises to an elevation of about 6,961 m (22,838 ft) above sea level. The peak of Chimborazo in the Ecuadorian Andes is farther from the Earth’s center than any other location on the Earth’s surface, due to the equatorial bulge resulting from the Earth’s rotation. The world’s highest volcanoes are in the Andes, including Ojos del Salado on the Chile-Argentina border, which rises to 6,893 m (22,615 ft). The Andes are also part of the American Cordillera, a chain of mountain ranges (cordillera) that consists of an almost continuous sequence of mountain ranges that form the western “backbone” of North America, Central America, South America and Antarctica.
The Tibetan Plateau
The Tibetan Plateau is a vast elevated plateau in Central Asia and East Asia, covering most of the Tibet Autonomous Region and Qinghai in western China, as well as Ladakh (Jammu and Kashmir) and Lahaul & Spiti (Himachal Pradesh) in India. It stretches approximately 1,000 kilometres (620 mi) north to south and 2,500 kilometres (1,600 mi) east to west. With an average elevation exceeding 4,500 metres (14,800 ft), the Tibetan Plateau is sometimes called “the Roof of the World” because it stands over 3 miles (4.8 km) above sea level and is surrounded by imposing mountain ranges that harbor the world’s two highest summits, Mount Everest and K2, and is the world’s highest and largest plateau, with an area of 2,500,000 square kilometres (970,000 sq mi) (about five times the size of Metropolitan France). Sometimes termed the Third Pole, the Tibetan Plateau contains the headwaters of the drainage basinsof most of the streams in surrounding regions. Its tens of thousands of glaciers and other geographical and ecological features serve as a “water tower” storing water and maintaining flow. The impact of global warming on the Tibetan Plateau is of intense scientific interest.