The Caribbean Sea (Spanish: Mar Caribe; French: Mer des Caraïbes; Dutch: Caraïbische Zee) is a sea of the Atlantic Ocean in the tropics of the Western Hemisphere. It is bounded by Mexico and Central America to the west and south-west, to the north by the Greater Antilles starting with Cuba, to the east by the Lesser Antilles, and to the south by the north coast of South America.

The entire area of the Caribbean Sea, the numerous islands of the West Indies, and adjacent coasts are collectively known as the Caribbean. The Caribbean Sea is one of the largest seas and has an area of about 2,754,000 km2 (1,063,000 sq mi).[1][2] The sea's deepest point is the Cayman Trough, between the Cayman Islands and Jamaica, at 7,686 m (25,217 ft) below sea level. The Caribbean coastline has many gulfs and bays: the Gulf of Gonâve, Gulf of Venezuela, Gulf of Darién, Golfo de los Mosquitos, Gulf of Paria and Gulf of Honduras.

The Caribbean Sea has the world's second biggest barrier reef, the Mesoamerican Barrier Reef. It runs 1,000 km (620 mi) along the coasts of Mexico, Belize, Guatemala, and Honduras.[3]

The Ganges (/ˈɡændʒiːz/ GAN-jeez), also known as Ganga (Hindustani: [ˈɡəŋɡaː]), is a trans-boundary river of Asia which 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 River 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 also empties into the Bay of Bengal. The Ganges is the third largest river in the world by discharge.[citation needed]

The Ganga is one of the most sacred rivers to Hindus.[4] It is also a lifeline to millions of Indians who live along its course and depend on it for their daily needs. It is worshipped in Hinduism as the goddess Ganga.[5] It has also been important historically, with many former provincial or imperial capitals (such as [6] Kannauj, Kampilya, [6] Kara, Prayag or Allahabad, Kashi, Pataliputra or Patna, Hajipur, Munger, Bhagalpur, Murshidabad, Baharampur, Nabadwip, Saptagram, Kolkata and Dhaka) located on its banks.

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.[7] 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.[7] The Ganga Action Plan, an environmental initiative to clean up the river, has been a major failure thus far,[a][b][8] due to corruption, lack of technical expertise,[c] poor environmental planning,[d] and lack of support from religious authorities.[e]

The Mekong is a trans-boundary river in Southeast Asia. It is the world's twelfth longest river[2] and the seventh longest in Asia. Its estimated length is 4,350 km (2,703 mi),[2] and it drains an area of 795,000 km2 (307,000 sq mi), discharging 475 km3 (114 cubic mi) of water annually.[3]
From the Tibetan Plateau, the river runs through China's Yunnan Province, Myanmar, Laos, Thailand, Cambodia, and Vietnam. In 1995, Laos, Thailand, Cambodia, and Vietnam established the Mekong River Commission (MRC) to manage and coordinate the use of the Mekong's resources. In 1996 China and Myanmar became "dialogue partners" of the MRC and the six countries now work together in a cooperative framework.

The Niger River (/ˈnaɪdʒər/; French: (le) fleuve Niger, pronounced [(lə) flœv niʒɛʁ]) 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.[3] 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 Congo River (also spelled Kongo River and known as the Zaire River; French: (le) fleuve Congo/Zaïre; Portuguese: rio Congo/Zaire; Kongo: Nzâdi Kôngo) is the second longest river in Africa after the Nile and the second largest river in the world by discharge volume of water (after the Amazon), and the world's deepest river with measured depths in excess of 220 m (720 ft).[2] The Congo-Chambeshi River 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 Congo River has a total length of 4,370 km (2,715 mi). It is the only river to cross the equator twice.[3] 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 Nile (Arabic: النيل‎) is a major north-flowing river in northeastern Africa and is commonly regarded as the longest river in the world,[1] though some sources cite the Amazon River as the longest.[2]The Nile, which is 6,853 km (4,258 miles) 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.[3] In particular, the Nile is the primary water source of Egypt and Sudan.[4]The river Nile has two major tributaries, the White Nile and the 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[5] and flows into Sudan from the southeast. The two rivers meet just north of the Sudanese capital of Khartoum.[6]

The Black Sea has a positive water balance; that is, a net outflow of water 300 km3 (72 cubic mi) per year through the Bosphorus and the Dardanelles into the Aegean Sea. Mediterranean water flows into the Black Sea as part of a two-way hydrological exchange. The Black Sea outflow is cooler and less saline and floats over the warm, more saline Mediterranean inflow – as a result of differences in density caused by differences in salinity – leading to a significant anoxic layer well below the surface waters. The Black Sea drains into the Mediterranean Sea, via the Aegean Sea and various straits, and is navigable to the Atlantic Ocean. The Bosphorus Strait connects it to the Sea of Marmara, and the Strait of the Dardanelles connects that sea to the Aegean Sea region of the Mediterranean. These waters separate Eastern Europe, the Caucasus, and Western Asia. The Black Sea is also connected to the Sea of Azov by the Strait of Kerch.

The Danube or Donau (/ˈdæn.juːb/ DAN-yoob, known by various names in other languages) 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 2,860 km (1,780 mi), passing through or touching the border of Austria, Slovakia, Hungary, Croatia, Serbia, Romania, Bulgaria, Moldova and Ukraine before emptying into the Black Sea. Its drainage basin extends into nine more countries. The Danube river basin is the most biodiverse region in Europe, and is home to hundreds of 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.

The Rhine (Latin: Rhenus, Romansh: Rein, German: Rhein, French: le Rhin,[1] , Italian: Reno, Dutch: Rijn) is a European river that 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),[note 2][note 1] 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.

The Persian Gulf (Persian: خلیج فارس‎, translator. Xalij-e Fârs, lit. 'Gulf of Fars'), (Arabic: الخليج الفارسي‎) is a mediterranean sea in Western Asia. The body of water is an extension of the Indian Ocean (Gulf of Oman) through the Strait of Hormuz and lies between Iran to the northeast and the Arabian Peninsula to the southwest.[1] The Shatt al-Arab river delta forms the northwest shoreline. The Persian Gulf was a battlefield of the 1980–1988 Iran–Iraq War, in which each side attacked the other's oil tankers. It is the namesake of the 1991 Gulf War, the large air- and land-based conflict that followed Iraq's invasion of Kuwait.

The gulf has many fishing grounds, extensive reefs (mostly rocky, but also coral), and abundant pearl oysters, but its ecology has been damaged by industrialization and oil spills. The body of water is historically and internationally known as the "Persian Gulf".[2][3][4] Some Arab governments refer to it as the "Arabian Gulf" (Arabic: الخليج العربي‎, translate. Al-Khalīj al-ˁArabī) or "The Gulf",[5] but neither term is recognized internationally. The name "Gulf of Iran (Persian Gulf)" is used by the International Hydrographic Organization.[6]The Persian Gulf is geologically very young, having been formed around 15,000 years ago.[7]

The Yangtze (English: /ˈjæŋtsi/ or /ˈjɑːŋtsi/), which is 6,380 km (3,964 mi) long, is the longest river in Asia and the third-longest in the world. The river is the longest in the world to flow entirely within one country. It drains one-fifth of the land area of the People's Republic of China (PRC) and its river basin is home to nearly one-third of the country's population.[6] The Yangtze is the sixth-largest river by discharge volume in the world.Map of the Yangtze River basin Golden Island, on The Yangtze River, China (LMS, 1869, p.64)[7] The English name Yangtze derives from the Chinese name Yángzǐ Jiāng (About this sound listen), which refers to the lowest 435 km (270 mi) of the river between Nanjing and Shanghai. The whole river is known in China as Cháng Jiāng (About this sound listen; literally: "Long River"). The Yangtze plays a large role in the history, culture and economy of China. The prosperous Yangtze River Delta generates as much as 20% of the PRC's GDP. The Yangtze River flows through a wide array of ecosystems and is habitat to several endemic and endangered species including the Chinese alligator, the narrow-ridged finless porpoise, the Chinese paddlefish, the (possibly extinct) Yangtze River dolphin or baiji, and the Yangtze sturgeon. For thousands of years, the river has been used for water, irrigation, sanitation, transportation, industry, boundary-marking and war. The Three Gorges Dam on the Yangtze River is the largest hydroelectric power station in the world.[8][9]In recent years, the river has suffered from industrial pollution, agricultural runoff, siltation, and loss of wetland and lakes, which exacerbates seasonal flooding. Some sections of the river are now protected as nature reserves. A stretch of the upstream Yangtze flowing through deep gorges in western Yunnan is part of the Three Parallel Rivers of Yunnan Protected Areas, a UNESCO World Heritage Site. In mid-2014, the Chinese government announced it was building a multi-tier transport network, comprising railways, roads and airports, to create a new economic belt alongside the river.[10]

The Great Lakes (French: les Grands-Lacs), also called the Laurentian Great Lakes[1] and the Great Lakes of North America, are a series of interconnected freshwater lakes located primarily in the upper mid-east region of North America, on the Canada–United States border, which connect to the Atlantic Ocean through the Saint Lawrence River. They consist of Lakes Superior, Michigan, Huron (or Michigan–Huron), Erie, and Ontario. The Great Lakes are the largest group of freshwater lakes on Earth by total area, and second largest by total volume, containing 21% of the world's surface fresh water by volume.[2][3][4] The total surface is 94,250 square miles (244,106 km2), and the total volume (measured at the low water datum) is 5,439 cubic miles (22,671 km3)[5], slightly less than the volume of Lake Baikal (23,615 km³, 22–23% of the world's surface fresh water). Due to their sea-like characteristics (rolling waves, sustained winds, strong currents, great depths, and distant horizons) the five Great Lakes have also long been referred to as inland seas.[6] Lake Superior is the second largest lake in the world by area, and the largest freshwater lake by area. Lake Michigan is the largest lake that is entirely within one country.[7][8][9][10] The Great Lakes began to form at the end of the last glacial period around 14,000 years ago, as retreating ice sheets exposed the basins they had carved into the land which then filled with meltwater.[11] The lakes have been a major highway for transportation, migration, and trade, and they are home to a large number of aquatic species. Many invasive species have been introduced due to trade, and some threaten the region's biodiversity.The surrounding region is called the Great Lakes region, which includes the Great Lakes Megalopolis.[12]

The Amazon River (US: /ˈæməzɒn/, UK: /-zən/; Spanish and Portuguese: Amazonas) in South America is the largest river by discharge volume of water in the world, and either the longest or second longest.[2][4][1]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 Cordillera Rumi Cruz at the headwaters of the Mantaro River in Peru.[10] 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[11] to form what Brazilians call the Amazon at the Meeting of Waters (Portuguese: Encontro das Águas) 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.[12] 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 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.[13][14]

The South China Sea is a marginal sea that is part of the Pacific Ocean, encompassing an area from the Karimata and Malacca Straits to the Strait of Taiwan of around 3,500,000 square kilometres (1,400,000 sq mi). The sea carries tremendous strategic importance; one-third of the world's shipping passes through it carrying over $3 trillion in trade each year,[3] it contains lucrative fisheries that are crucial for the food security of millions in Southeast Asia, and huge oil and gas reserves are believed to lie beneath its seabed.[4] According to International Hydrographic Organization (IHO) Limits of Oceans and Seas, 3rd edition (1953), it is located[5]
south of China;east of Vietnam;west of the Philippines;east of the Malay peninsula and Sumatra, up to the Strait of Singapore in the western, and north of the Bangka Belitung Islands and Borneo However, in its unapproved draft 4th edition (1986),[6] IHO proposed the Natuna Sea, thus the South China Sea southern boundary was shifted northward, from north of Bangka Belitung Islands to north and northeast of Natuna Islands.[7] The minute South China Sea Islands, collectively an archipelago, number in the hundreds. The sea and its mostly uninhabited islands are subject to competing claims of sovereignty by several countries. These claims are also reflected in the variety of names used for the islands and the sea.