Geography

The Jordan River

rises in Syria from springs near Mount Hermon. It flows south to Lake Merom, through the Sea of Galilee, and into the Dead Sea, which is 1,300 feet below sea level. The river forms the nation of Jordan's boundary with the West Bank and northern Israel. In the New Testament, the river was the site of the baptism of John the Baptist. In modern times, about 80% of its water is diverted for human use, a figure that has led to the shrinking of the Dead Sea and serious contention among bordering nations.

Po

Italy's longest river at 405 miles, it passes through Piedmont and Lombardy before entering the Adriatic 30 miles south of Venice. It flows through Turin and Cremona, and it passes near Milan, Padua, Pavia, and Mantua. The river has a long history of floods, and the manmade levees called argini which protect towns and crops can exacerbate the floods. Pollution, especially from Milan, is becoming a major environmental concern.

Rub' al-Khali (Arabian Peninsula; 250,000 mi2)

Its name means "Empty Quarter" in English, is sometimes considered the most inhospitable place on earth. It is known for the world's largest oil field, the Ghawar, and for once being part of the frankincense trade.

The Irrawaddy

(or Ayeyarwaddy) is the chief river of Myanmar (also known as Burma). It flows 1,350 miles past Yangon (formerly Rangoon) and Mandalay to the Gulf of Martaban, an arm of the Bay of Bengal. Its delta is one of the world's most important rice-growing regions, and its name is thought to come from the Sanskrit word for "elephant."

The Yangtze

(or Chang Jiang or Ch'ang Chiang) is the longest river in China and Asia, and the third longest in the world. It rises in the Kunlun Mountains, flows across the Tibetan Plateau, passes the cities of Chongqing, Wuhan, Nanjing, and Shanghai, and empties into the South China Sea. Its basin is China's granary and is home to nearly a third of Chinese citizens. The river is dammed by the Three Gorges Dam, the world's largest, which reduced flooding but displaced 1.5 million people and buried over 1,300 known archaeological sites.

The Ganges

(or Ganga) is the holiest river of Hinduism. It rises in the Himalayas and flows a comparatively short 1,560 miles to the world's largest delta, on the Bay of Bengal. Among that delta's distributaries are the Hooghly (on whose banks Kolkata — formerly Calcutta — may be found) and the Padma (which enters Bangladesh). Approximately one in every twelve human beings lives in the Ganges Basin, a population density that is rapidly polluting the river; a significant source of that pollution is cremated remains.

The Yellow River

(or Huang He or Huang Ho) is, at 3,400 miles, China's second-longest; it is also the most important to the northern half of the country. It rises in Qinghai province and flows into the Bohai Gulf of the Yellow Sea. The river's name comes from the extraordinary amount of loess silt that it carries, an average of 57 pounds for every cubic yard of water. Among its notable features is the Grand Canal, built during the Ming Dynasty, that links it to the Yangtze.

Lake Malawi

(or Lake Nyasa) Africa's third-largest lake by area and the southernmost of the Great Rift Valley lakes, it is wedged between the nations of Malawi, Tanzania, and Mozambique. Fed by the Ruhuhu River, its lone outlet is the Shire River, a tributary of the Zambezi. Lake Malawi contains hundreds of species of endemic fish, especially cichlids.

The Brahmaputra

(or Tsangpo or Jamuna) runs 1,800 miles from its source in the Tibetan Himalayas; it starts eastward across the plateau, then turns south into the Indian state of Assam, and then enters Bangladesh, where it merges with the Ganges to form the world's largest delta. While serving as a historical route to Tibet, the river is also prone to disastrous flooding.

Lake Chad Formerly

Africa's fourth-largest lake, its surface area has been reduced by over 90% since the 1960s due to droughts and diversion of water from such sources as the Chari River. The lake is at the intersection of Chad, Cameroon, Niger, and Nigeria, but most of the remaining water is in Chad and Cameroon. Lake Chad is very shallow and has no outlet, so seasonal rainfall causes large fluctuations in its area.

Lake Victoria

Africa's largest and the world's second-largest freshwater lake by area, Lake Victoria lies along the Equator and is shared among Uganda, Kenya, and Tanzania. Located on a plateau between two rift valleys, its lone outlet is the Victoria Nile, a precursor of the White Nile. Named by the British explorer John Hanning Speke after Queen Victoria, the introduction of the predatory Nile perch in the 1950s has caused environmental degradation, sending many native cichlid species into extinction.

Lake Tanganyika

Africa's second-largest lake by area, it is also the second-deepest in the world, surpassed only by Lake Baikal. Due its extreme depth (over 4,700 feet), Lake Tanganyika contains seven times as much water as Lake Victoria. A source of the Lualaba River, it is shared by Tanzania, the Democratic Republic of the Congo, Burundi, and Zambia. On its Tanzanian shore is the town of Ujiji, at which Henry Morton Stanley "found" Dr. David Livingstone in 1871.

Congo River

Africa's second-longest river, it flows in a counterclockwise arc some 2,900 miles to the Atlantic Ocean. The Upper Congo's principal sources are the Lualaba, which rises in the Democratic Republic of the Congo's Katanga province, and Zambia's Chambeshi River. Boyoma Falls (formerly Stanley Falls), a section of seven cataracts near Kisangani, marks the beginning of the Congo River proper. Forming the Malebo Pool near the world capitals of Kinshasa and Brazzaville, the Lower Congo flows past Angola's Cabinda exclave as it enters the ocean. Joseph Conrad's Heart of Darkness depicts the often cruel conditions the Congo basin endured as a Belgian colony.

Niger River

Africa's third-longest, it flows in a great clockwise arc through Guinea, Mali, Niger, and Nigeria before entering the Gulf of Guinea. The medieval Mali and Songhai Empires were centered on the Niger, whose course was mapped by the Scottish explorer Mungo Park in the 1790s. In Nigeria, it receives the Benue River, its main tributary. The massive Niger Delta, known for its fisheries, wildlife, and petroleum, is an area of increasing social unrest.

Oder

Along with the Neisse, the Oder forms the Germany-Poland border, as dictated at the Potsdam Conference in July and August of 1945. One of the largest rivers to enter the Baltic, it has been a major transport route for centuries. Ostrava in the Czech Republic and Breslau in Poland are on the river. Near its mouth is Stettin, which Churchill used as the northern terminus of his "Iron Curtain" (Trieste, in the South, is an Adriatic port not near a major river). At the mouth of the Oder are Usedom Island, Swinemuende, and Peenemuende, which were primary test sites for the German V-2 rocket in the 1940s.

Shannon

At 230 miles, the Shannon is Ireland's longest river. It flows from Lough Allen, and Loughs Ree and Derg are also on its course. At Limerick, the river widens into its namesake estuary and runs for 50 more miles before it enters the Atlantic. Peat bogs and marshes line the river for much of its course, and the Shannon is considered a dividing line between Ireland's more cultivated east and wild west. A chief tributary is the Suck River. The Shannon does not pass through Dublin, although the Liffey does.

Antarctica (5.4 million mi2)

Because it is covered with (solid) water, it is somewhat surprising that Antarctica is considered a desert, but it is classified as such due to its lack of precipitation. Players should be familiar with its tallest mountain, Vinson Massif in the Ellsworth Mountains; its active volcano Mount Erebus; the surrounding Ross and Weddell Seas; and the Ross Ice Shelf. The Norwegian explorer Roald Amundsen was the first to reach the South Pole (1911), while the Englishman Robert Scott died trying to reach it. Ernest Shackleton had to abandon his ship, the Endurance, during an attempt to cross Antarctica on foot.

The Matterhorn

Edward Compton and John Ruskin are among the artists inspired by the Matterhorn, which is renowned for its almost perfectly pyramidal shape. The mountain is on the border between Switzerland and Italy, near the Swiss town Zermatt. It was first climbed in 1865 by Edward Whymper; four people died in that ascent.

Denali

Formerly and often called Mount McKinley, Denali is the highest mountain in North America. It is in south-central Alaska, in Denali National Park. The West Buttress route is considered the best path to ascend Denali. Frederick Cook, a man notorious for having faked the discovery of the North Pole, is now believed to have also faked his ascent of the mountain in 1906 as well, leaving a climbing party seven years later with the honor.

Loire

France's longest river, the Loire begins in the Cevennes range of southern France, flows north to the center of the country, then flows due west to the Bay of Biscay. Many notable cities are on the river, including Nevers, Orleans, Blois, Tours, and Nantes. The Loire is sometimes called the "last wild river in Western Europe," and many proposed dams on the river have not been built because of opposition to the flooding of land and to interference with Atlantic salmon. The Loire Valley is particularly known for its vineyards and for its châteaux, a collection of over 300 castles dating to the 16th and 17th centuries.

Mount Kilimanjaro

Kibo, Mawenzi, and Shira are the three summits of Mount Kilimanjaro, the tallest mountain in Africa. It is notable for also being the tallest mountain that is not part of a mountain range, having been formed by a now-extinct volcano. A corpse of a leopard is found on top of the mountain in "The Snows of Kilimanjaro," a short story by Ernest Hemingway that uses the mountain as the backdrop for the memories, and ultimately the death, of a writer suffering from gangrene.

Danube

Most of the Danube is in Eastern Europe, but it begins in Germany's Black Forest (Schwarzwald) near Freiburg, crossing Bavaria before it enters Austria. In all, it passes through (or touches the borders of) 10 nations on its 1,785-mile course ending at the Black Sea. Chief tributaries include the Drava and Sava, and it passes through four national capitals: Vienna, Bratislava, Budapest, and Belgrade. Formerly known as the Ister, the Danube was often used to define a northern border for the Roman Empire.

Thames

Running from Thames Head near Cirencester to an estuary near Southend in Essex, the Thames is the principal river of England and flows through central London. The Houses of Parliament and the London Eye overlook the Thames, as does Big Ben. Flowing through Reading, Oxford, and Swindon, the Thames is prevented from flooding London by its namesake Barrier near the Isle of Dogs. Though it is the longest river entirely in England, the Thames trails the Severn (which also flows into Wales) as the longest river in the United Kingdom.

Rhone

One of Europe's few major rivers to flow directly into the Mediterranean (via the Gulf of Lion), the Rhone originates in the Swiss Alps and flows into Lake Geneva. It emerges from Geneva and flows south, passes through Lyon, Avignon, and Arles, and enters the sea just west of Marseille. At Arles, the river splits into "grand" and "petit" branches that encircle the island Camargue. The river's valley is famous for its red wine, and because it is navigable for 300 miles, the Rhone is the key access route of southern France.

Great Sandy Desert (Western Australia; 140,000 mi2)

Part of the Western Desert, and the ninth largest in the world.

K2

Qogir, Ketu, and Mount Godwin-Austen are other names for K2, whose most common names come from the fact that it is the second-tallest mountain in the world. The "K" in K2 stands for Karakoram, the mountain range in Pakistan and China in which the peak is found. The House's Chimney and the Black Pyramid are features of K2, which also possesses a different second-place record, behind the Annapurna Massif: it boasts the second-highest fatality rate among attempted climbers of any mountains above 8,000 meters.

Limpopo River

Rising as the Crocodile (or Krokodil) River in South Africa's Witwatersrand region, it forms the Transvaal's border with Botswana and Zimbabwe, then crosses through Mozambique. Deforestation in Mozambique contributed to massive flooding of the Limpopo in 2000. Perhaps the most famous description of the Limpopo comes from Rudyard Kipling, who in "The Elephant's Child" referred to it as "the great grey-green, greasy Limpopo River, all set about with fever-trees."

Elbe (or Labe)

Rising in the Krkonose Mountains of the Sudetenland in the Czech Republic, the river flows near Prague, then enters eastern Germany and flows northwest to the North Sea. It receives the Vltava (or Moldau), the Saale, and the Havel/Spree, and the many large cities on its course include Dresden, Dessau, Magdeburg, Wittenberg, and Hamburg. Like the Oder, the Elbe has been a key transportation route for many centuries.

Atacama Desert (Chile; 70,000 mi2)

The Atacama's chief claim to fame is the rain shadow of the Andes, which makes it the driest hot desert in the world. The desert was the primary bone of contention in the War of the Pacific (1879 1883; Chile defeated Peru and Bolivia) that sought to control its nitrate resources, which were necessary for the production of explosives.

Mount Mitchell

The Black Mountain subrange of the Appalachians is the location of Mount Mitchell, the tallest peak in the United States east of the Mississippi. This mountain, in North Carolina, was the subject of a debate over its altitude between its namesake and Thomas Clingman, leading Elisha Mitchell to attempt another ascent in which he fell to his death.

Gobi Desert (China and Mongolia; 500,000 mi2)

The Gobi, Asia's second largest desert (after the Arabian Desert), is bounded on the north by the Altai Mountains. It is known for its role in the Silk Road trading route and the Nemegt Basin, where fossilized dinosaur eggs and human artifacts have been found.

Kalahari Desert (Botswana, Namibia, South Africa; 360,000 mi2)

The Kalahari is a large region, not all of which is arid enough to qualify as a desert. It is known for its red sand, large game reserves (meerkats, gemsbok, springbok, steenbok), and mineral deposits (notably uranium). Its San Bushmen speak a click language.

Mojave moh-HAH-vay Desert (mostly California, and some of Arizona, Utah, and Nevada; 25,000 mi2)

The Mojave is bounded by the San Gabriel and San Bernardino mountain ranges along the San Andreas and Garlock Faults. It is between the Great Basin and the Sonoran Desert, and it contains the lowest and driest point of North America, Death Valley. It is most strongly associated with the Joshua tree (Yucca brevifolia).

Namib Desert (Namibia and Angola; 30,000 mi2)

The Namib, a coastal desert, is known for its bizarre Welwitschia and medicinal Hoodia plants. It is thought to be the oldest desert in the world.

Okavango River

The Okavango flows for about 1,000 miles from central Angola, through Namibia's Caprivi Strip, and into the Kalahari Desert of Botswana. There, rather than flowing into the sea, it terminates in a massive inland swamp known as the Okavango Delta, an area that — especially during the wet season — teems with wildlife in an otherwise inhospitable region.

Painted Desert (Northern Arizona)

The Painted Desert, which is shared by Grand Canyon and Petrified Forest National Parks, is known for its colorful, banded rock formations.

Rhine

The Rhine begins in the Swiss Alps, passes through Lake Constance (in German, the Bodensee), flows west along the German-Swiss border, then turns north to form part of the German-French border. The river then flows north and joins with the Meuse and Scheldt to enter the North Sea at a delta in the Netherlands. Cities along its course include Basel, Strasbourg, Mainz, Bonn, Cologne, and Rotterdam, and tributaries include the Main, Mosel, and Ruhr. The Rhine has played a strategic role in most German conflicts since the time of the Gallic Wars, but was not established as an international waterway until the Rhine Commission of 1815. German myth tells of the Lorelei, a nymph who lured sailors on the Rhine to their deaths.

Sahara Desert (Northern Africa; 3.5 million mi2)

The Sahara is the world's second largest desert, but its largest hot desert. The Atlas Mountains bound the western Sahara on the north, and the Sahel — a savannah-like strip — bounds it on the south. It is dominated by rocky regions (hamada), sand seas (ergs), and salt flats (shatt) and dry river valleys (wadi) that are subject to flash floods. The Berber and Tuareg peoples are native to the Sahara.

Tagus (or Tajo or Tejo)

The Tagus is the principal river of the Iberian Peninsula. Rising in east-central Spain, it flows west for roughly 645 miles to the Atlantic, passing through Lisbon, Portugal on the way. The cities of Toledo and Santarém are on the Tagus, and hydroelectric dams on the river produce huge artificial lakes, including the Sea of Castile.

Taklamakan Desert (China; 105,000 mi2)

The Taklamakan is an extremely cold, sandy desert known for splitting the Silk Road into branches running north and south of it. It is bounded by the Kunlun, Pamir, and Tian Shan mountain ranges.

Mount Everest

The border between Nepal and China straddles the summit of the Himalayan peak Mount Everest, which, at a height of over 29,000 feet, is the tallest mountain in the world. The Khumbu Icefall and the cliff-like Three Steps are hazards faced by potential climbers of Everest. It was first summited by Sir Edmund Hillary and Tenzing Norgay in 1953. Local Sherpas act as guides for mountaineers in the area, though they walked out of the job over dangerous working conditions in 2014 after 16 of them were killed in an avalanche.

Lake Volta

The largest man-made lake (by area) in the world, Lake Volta was created by the construction of Ghana's Akosombo Dam across the Volta River in the 1960s. The lake covers the area where the Black Volta and White Volta rivers formerly converged. The Akosombo Dam can provide over a gigawatt of power, enough to supply nearby aluminum smelters utilizing the energy-intensive Hall-Héroult process and the needs of the rest of the country.

Mount Fuji

The name of Tadeusz Kosciuszko, the Polish commander who fought in the American Revolutionary War, was appended to the tallest mountain in Australia by European explorers in the 19th century. When it was discovered that Mount Townsend was actually taller, the names were switched so that Kosciuszko would remain the highest peak on the continent. The peak's name in Aboriginal languages, such as Jagungal or Tackingal, translates to "table-top mountain."

Mount Kosciuszko

The name of Tadeusz Kosciuszko, the Polish commander who fought in the American Revolutionary War, was appended to the tallest mountain in Australia by European explorers in the 19th century. When it was discovered that Mount Townsend was actually taller, the names were switched so that Kosciuszko would remain the highest peak on the continent. The peak's name in Aboriginal languages, such as Jagungal or Tackingal, translates to "table-top mountain."

Mount Kenya

The second-tallest mountain in Africa is Mount Kenya, which shares its name with the country in which it is located. British geographer and political theorist Halford Mackinder led the first group to ascend the peak, which bypassed the Darwin Glacier and proceeded up the Diamond Glacier. Like Kilimanjaro, it was formed by a now-dormant volcano, and, like Kilimanjaro, part of its notoriety rests on a book. Facing Mount Kenya, an anthropological study of the Kikuyu people by Jomo Kenyatta, was one of the first such texts by an African ethnographer to gain fame.

Mount Aconcagua

The subduction of the Nazca Plate formed Mount Aconcagua, the highest point in the Southern Hemisphere. It is near the city Mendoza in Argentina, and straddles the Polish Glacier, which provides a popular route for climbers looking to summit it.

Negev Desert (Israel; 4,700 mi2)

The triangular Negev covers the southern half of Israel.

Seine

Though only the second-longest river in France (behind the Loire), the Seine is of key importance, as it flows through Paris. Starting on the Plateau de Langres near Dijon, the Seine weaves northwest for 485 miles to enter the English Channel near Le Havre. Along the way, it passes through Troyes, Fontainebleau, and Rouen. The Seine is France's chief transport waterway, along with its tributaries the Marne and Oise.

Nile River

Usually cited as the longest river in the world, the Nile flows about 4,132 miles in a generally south-to-north direction from its headwaters in Burundi to Egypt's Mediterranean Sea coast, where it forms a prototypical delta. Over 80% of the Nile's flow comes from the shorter Blue Nile headstream, which arises from Ethiopia's Lake Tana and meets the longer White Nile — whose headwaters include Lake Victoria — at Khartoum. At the first of the Nile's six cataracts is the Aswan High Dam, which forms Lake Nasser and greatly reduces the annual floods.

Zambezi River

Weaving across southern Africa, the Zambezi rises in eastern Angola, passes through Zambia, flows along the borders of Namibia, Botswana, and Zimbabwe, crosses through Mozambique, and enters the Indian Ocean's Mozambique Channel near Chinde. Namibia's Caprivi Strip was created to allow access to the Zambezi. The Cabora Bassa and Kariba Dams form large lakes of the same name. The most spectacular feature of the Zambezi is Victoria Falls, or Mosi-oa-Tunya ("the smoke that thunders"), which is over a mile wide and is the largest waterfall by flow rate in Africa.

Mount Fuji

a stratovolcano on the island of Honshu, is Japan's tallest mountain. Mount Fuji is one of the "Three Holy Mountains" of Japan, along with Mount Haku and Mount Tate. Mount Fuji last erupted in December 1707 in the lava-less Hoei Eruption. Because of its beautiful shape, Mount Fuji is a frequent muse for artists, including the Japanese artist Katsushika Hokusai, whose woodblock series Thirty-Six Views of Mount Fuji includes The Great Wave off Kanagawa. Aokigahara, popularly known as the "Suicide Forest," is on the volcano's northwestern slope.

Mount Erebus

a stratovolcano, is the second-highest volcano in Antarctica (but tallest active one) and the southernmost active volcano in the world. Mount Erebus sits on Ross Island. It took its name from the primordial personification of darkness in Greek mythology. The northeast slope of Mount Erebus is known as "Fang Ridge," and the volcano's underground magma produces unique pieces of feldspar known as "Erebus crystals." In 1979 an Air New Zealand jet crashed into the side of Mount Erebus during a whiteout, killing over 250 people.

The Euphrates

defines the western border of Mesopotamia; it also rises in the Zagros Mountains of Turkey and its shores are home to Fallujah and Babylon. It is the longer of the two rivers, with a course of 1,740 miles (compared to the Tigris' 1,180). Both the Tigris and the Euphrates have changed courses several times, leaving ruins in the desert where cities have been abandoned.

The St. Lawrence River

drains the Great Lakes and serves as a major waterway of eastern Canada. First explored and named by Jacques Cartier in the early 16th century, the St. Lawrence emerges from the northeastern corner of Lake Ontario in the Thousand Islands archipelago, forming the border between Ontario and New York. The St. Lawrence receives the Ottawa and Saguenay Rivers and flows through Montréal and Quebec City. At its mouth, the Gulf of St. Lawrence is one of the world's largest estuaries.

The Ohio River

flows 981 miles through a significant industrial region of the central United States. Historically seen as the border between the northern and southern United States, the Ohio is formed in downtown Pittsburgh by the confluence of the Allegheny and Monongahela Rivers, flowing past Wheeling, Cincinnati, Louisville, and Evansville, forming borders of five states before emptying into the Mississippi at Cairo, Illinois. Other major tributaries of the Ohio include the Kanawha, Kentucky, Tennessee, Wabash, and Cumberland Rivers.

The Hudson River

has been a historically significant American river since the early 17th century. Named for the English explorer Henry Hudson, it flows 315 miles through eastern New York state. After receiving the Mohawk River, the Hudson flows past New York's capital, Albany, and West Point before forming the boundary between Manhattan and New Jersey. The Hudson is also culturally significant as an inspiration for Washington Irving and the Hudson River School of American landscape painters.

The Rio Grande

has formed the border between Texas and four Mexican states since 1848. It flows south out of Colorado through New Mexico before reaching the international boundary near El Paso. Texas's Big Bend National Park is named for the sweeping curve the Rio Grande cuts through the Sierra Madre Oriental. After leaving the mountains, the river flows past Laredo and Brownsville before it empties into the Gulf of Mexico.

The Delaware River

is a historically significant river of the eastern United States. From its source in the Catskills, the Delaware flows 301 miles, forming the border between Delaware and New Jersey. The Delaware flows past Trenton, New Jersey and Philadelphia, where it receives the Schuylkill River before emptying into the Atlantic. George Washington crossed the Delaware on Christmas night in 1776 to surprise the Hessians at the Battle of Trenton.

The Snake River

is a major river of the northwestern United States. Rising in Yellowstone National Park, the Snake bisects southern Idaho along its 1,078-mile route. Flowing through Pocatello and Boise, the Snake River forms much of the border between Idaho and Oregon, including the famous Hells Canyon. The Snake River was a vital route for travelers headed west on the Oregon Trail, who followed the river most of the way to its mouth on the Columbia River.

The Red River

is a major river of the southern Great Plains. The Red River forms most of the border between Oklahoma and Texas along its 1,360-mile length. That border formed part of the border between Mexico (and later the Republic of Texas) and the United States after the 1819 Adams-Onís Treaty. The Red runs through the Louisiana cities Shreveport and Alexandria before emptying into the Mississippi south of Natchez, Mississippi.

Mauna Loa

is a shield volcano on the Big Island of Hawaii that is the most massive above-sea volcano on Earth. It should not be confused with Mauna Kea, a dormant volcano that is the tallest mountain in Hawaii. Both Mauna Kea and Mauna Loa are taller than Mount Everest when measuring from base-to-summit rather than from sea level. Along with Kilauea, Mauna Loa forms the Hawaiʻi Volcanoes National Park, which was established in 1916 by Woodrow Wilson. When Mauna Loa erupted in 1942, four months after the attack on Pearl Harbor, the U.S. government gagged the press from reporting on the eruption.

Kilauea

is a shield volcano that is the most active of the five volcanoes on the Big Island of Hawaii. The name "Kilauea" means "spewing" or "spreading" in the Hawaiian language. In Hawaiian mythology, the volcano is the home of the fire goddess Pele. The three primary craters of Kilauea are Halemaʻumaʻu Crater, Puʻu Crater, and Puʻu ʻOʻo Crater. In addition, part of the volcano is covered by the Kaʻu Desert, a plain of dried lava and volcanic ash. The Hawaiian Volcano Observatory is on the rim of Kilauea's caldera.

Krakatoa

is a stratovolcanic island in the Sunda Strait between the Indonesian islands of Sumatra and Java. Prior to its massive 1883 eruption, there were three separate volcanic peaks: Perboewatan (completely destroyed by the eruption), Rakata (extant), and Danan (almost completely destroyed). The 1883 eruption of Krakatoa killed more than 35,000 people and is believed to have produced the loudest sound ever. Krakatoa is one of the largest volcanoes in the Pacific Ring of Fire. The continued activity of Krakatoa formed a new island, Anak Krakatau (or "Child of Krakatoa") in 1927.

Mount Etna

is a stratovolcano in eastern Sicily that plays a significant role in ancient Greek myths. Zeus trapped the monster Typhon under Mount Etna, and the volcano is also the site of Hephaestus's forges. Mount Etna overlooks the Sicilian town of Catania. It most recently erupted in 2015. Earlier eruptions occurred in 1928 (destroying the village of Mascali) and in 1669, after which the volcano was thought to have gone dormant. There is a large depression on the side of Mount Etna known as Valle del Bove, or "Valley of the Ox."

Mount Pinatubo

is a stratovolcano in the Zambales Mountains on the eastern coast of the island of Luzon in the Philippines. In the aftermath of its 1991 eruption, the global temperature briefly decreased by almost a full degree Fahrenheit due to the ejection of aerosols and sulfuric acid. That eruption was ten times more powerful than the 1980 eruption of Mount Saint Helens; it killed at least 800 people and forced the evacuation of some 20,000 people. In its aftermath, monsoon rains created Lake Pinatubo in the resulting crater. In 2010, the indigenous Aeta people were formally granted domain over the volcano.

Mount Vesuvius

is a stratovolcano on the Gulf of Naples in Campania in south-central Italy. Mount Vesuvius, which last erupted in 1944, is the only active volcano on mainland Europe. The most notable eruption of Mount Vesuvius was in AD 79 when it buried the Roman cities of Pompeii, Herculaneum, and Stabiae. The only surviving eyewitness accounts of that eruption are a pair of letters written by Pliny the Younger to Tacitus. The 1908 Summer Olympics were relocated from Rome to London after a surprise eruption of Mount Vesuvius.

Mount Rainier

is a stratovolcano that is the highest peak in the Cascades and in the state of Washington. It is located about 50 miles southeast of Seattle. The three principal peaks of Mount Rainier are Columbia Crest (the tallest), Point Success, and Liberty Cap; the Little Tahoma Peak is a remnant of an older, much larger Mount Rainier that has since eroded away. Mount Rainier has not erupted since the mid-to-late nineteenth century. The Nisqually Glacier, on Mount Rainier's southwestern slope, is used to track climate change. The Emmons Glacier on Mount Rainier is the largest glacier by area in the contiguous U.S., while the Carbon Glacier is the largest by volume. The entirety of Mount Rainier is in Mount Rainier National Park, the fifth national park established in the U.S.

The Columbia River

is a vital waterway of the Pacific Northwest. Rising in the Rockies of British Columbia, the Columbia flows through Lake Revelstoke before entering Washington state. Grand Coulee Dam along the Columbia in Washington forms Lake Roosevelt. When it was completed in 1943, Grand Coulee was the largest hydroelectric plant in the world; it is still America's largest electric power plant. The Columbia receives the Yakima and Snake Rivers before forming much of the Washington-Oregon border, receiving the Willamette River in Portland before emptying into the Pacific where Lewis and Clark sighted the ocean.

Mount Saint Helens

is another stratovolcano in the Cascades of Washington state. It is about 100 miles south of Seattle and about 50 miles north of Portland. It last erupted in May 1980, killing 57 people in the most devastating volcanic eruption in U.S. history. Perhaps the most famous casualty of that eruption was an innkeeper named Harry Truman (no relation to the president of the same name) who refused to evacuate from the mountain. Because of an avalanche of volcanic debris during that eruption, Mount Saint Helens lost about 1300 feet in height; lahars (mudflows of pyroclastic material) reached all the way to the Columbia River. The volcano is surrounded by Gifford Pinchot National Forest.

The Missouri River

is formed in western Montana by the confluence of the Jefferson, Madison, and Gallatin Rivers. It flows past Bismarck, North Dakota and Kansas City before emptying into the Mississippi just north of St. Louis. Lewis and Clark used the Missouri as a route for exploration of the Louisiana Purchase. The Missouri is regulated by a number of major dams, including Fort Peck in Montana and Oahe Dam in South Dakota.

The Potomac River

is one of America's most historic waterways. Rising at Fairfax Stone in West Virginia, the Potomac runs 405 miles, forming the border between Virginia and Maryland. Washington, D.C. was sited on the Potomac at its confluence with the Anacostia River. George Washington's plantation Mount Vernon was on the Potomac, while Robert E. Lee's two invasions north of the Potomac were major events of the Civil War.

The Indus

is the chief river of Pakistan and the source of the name of India. It rises in Tibet and flows 1,800 miles to a delta on the Arabian Sea southeast of Karachi. The five major tributaries of the Indus — the Jhelum, Chenab, Ravi, Beas, and Sutlej Rivers — are the source of the name of the Punjab region, which is Persian for "land of the five rivers." The Indus is the cradle of the Indus Valley Civilization, one of the world's earliest urban areas, whose main cities were Mohenjo-Daro and Harappa.

The Mekong

is the chief river of Southeast Asia. It originates in eastern Tibet, forms much of the Laos-Thailand border, flows south through Cambodia, and enters the South China Sea in southern Vietnam just south of Ho Chi Minh City. The capital cities Vientiane and Phnom Penh are on the Mekong. The building of dams and clearing of rapids are a source of diplomatic conflict among China, Laos, and Cambodia.

The Tigris

is the eastern of the two rivers that define the historic region Mesopotamia (meaning "the Land Between Two Rivers"), which was home to the ancient civilizations Sumer and Akkad. It rises in Turkey, then flows southeast by Mosul, Tikrit, and Baghdad before joining the Euphrates to make the Shatt-al-Arab, which empties into the Persian Gulf.

The Mississippi River

is the longest or second-longest in North America, depending on how you count. (The Missouri River could be considered longer.) Referred to by Abraham Lincoln as "the father of waters," the Mississippi begins at Lake Itasca, Minnesota, and flows 2,340 miles to a vast delta on the Gulf of Mexico, forming portions of ten state borders and the world's third-largest drainage basin. The Mississippi picks up numerous major tributaries including the Illinois, Missouri, Ohio, Arkansas, and Red Rivers, and flows past numerous major cities, including Minneapolis, St. Louis, Memphis, and New Orleans.

The Mackenzie River

is the longest river of Canada. Flowing 1,080 miles out of the Great Slave Lake, the river flows past Fort Providence and Fort Simpson in Canada's Northwest Territories, emptying into a vast delta on the Beaufort Sea. The Mackenzie is the largest river flowing into the Arctic Ocean from North America. The river was named for Scottish explorer Alexander Mackenzie, who crossed Canada to the Pacific ten years before Lewis and Clark.

The Colorado River

is the most significant river of the southwestern United States. Beginning in Rocky Mountain National Park in Colorado, the Colorado River runs southwest for 1,450 miles to the Gulf of California in northwestern Mexico. The Colorado formed numerous canyons along much of its length, most notably the Grand Canyon in Arizona. The Colorado also has significant dams, including Hoover Dam near Las Vegas (forming Lake Mead) and Glen Canyon Dam in Arizona (forming Lake Powell).