Down by the River Trivia Quiz

Answer: Potomac

Ronald Reagan National Airport is one of Washington DC's two airports, and the one closest to the centre of the US national capital, which lies just across the Potomac River. Some of the airport's runways look almost uncomfortably close to the water, especially if seen from above. The 21st-largest river in the US in terms of drainage area, the Potomac (main stem and North Branch) is 652 km (405 mi) long; the two branches join in West Virginia, and flow south-east towards the Chesapeake Bay, forming a boundary between Washington DC and the states of Maryland and Virginia. Many important landmarks can be seen from the river, such as the Washington Monument (mentioned in the question), the Lincoln and Jefferson Memorials, the Pentagon, and George Washington's home at Mount Vernon.

The remaining options are all major rivers found in the US Mid-Atlantic region.

Answer: Manaus

Manaus, the capital of the Brazilian state of Amazonas, has a population of about 2 million. Because of its unique location, it is generally reached by boat or plane, though in recent years roads have been built that pass close to the city. Manaus was founded in the late 17th century as a fort named Fort de São José da Barra do Rio Negro, then elevated to town status in 1832 with the name of Manaus (after the indigenous Manaós people). In the late 19th century, the rubber boom made Manaus the richest city in South America, nicknamed the Paris of the Tropics for its sophisticated and extravagant lifestyle - which included the introduction of electricity and the building of an opera house, the Teatro Amazonas. When the boom ended, the city underwent an abrupt decline, which lasted for most of the 20th century. In the 1960s, the introduction of a free trade zone and the opening of new roads encouraged the regrowth of the city's population. Now Manaus is one of Brazil's largest cities, with a thriving tourist industry that makes the most of the city's unique environment and culture. The Rio Negro ("black river") gets its name from the tannins from decaying vegetal matter that stain its water a dark brown colour; it is the Amazon's largest tributary (2,250 km/1,400 mi), and the one of the world's ten largest rivers in term of discharge. Solimões is the name given to the upper part of the Amazon River in Brazilian Portuguese.

The three remaining options are all major South American cities, two of them (Buenos Aires and Lima) also national capitals.

Answer: Kalahari

With a length of 1,700 km (1,056 mi), the Okavango is the fourth-longest river in southern Africa. It rises in Angola (where is known as Rio Cubango), then flows south-east into Botswana. Unlike most major rivers, the Okavango does not empty into the sea, but flows into a swamp in the Kalahari Desert, known as Okavango Delta or Okavango Alluvial Fan. This area is known for its rich and varied wildlife - which includes thousands of flamingos, which congregate there in the summer, when the swamp is fully flooded by the rains. The Moremi Game Reserve, which covers the eastern side of the Delta, is home to many of the continent's most iconic animal species, and attracts many visitors interested in experiencing an unspoiled environment, away from mass tourism.

The other choices are all important deserts, though none of them is found in southern Africa. Gobi and Negev are located in Asia, and Mojave in North America.

Answer: Khartoum

Founded in 1821 by Ibrahim Pasha of Egypt, Khartoum - originally a military settlement - was built on the narrow strip of land between the White Nile and the Blue Nile. After a troubled start, marked by flooding, outbreaks of disease and war, it developed into an important business and cultural centre. Khartoum's population is now more than 5 million; the city is divided into three parts - Khartoum proper, Khartoum North and Omdurman - linked by bridges that cross the two rivers. The White Nile flows north from Lake Victoria, while the Blue Nile flows west from the highlands of Ethiopia. The location where the two Niles meet is called "al-Mogran", meaning "the confluence"; then the river, the world's longest, flows north towards Egypt, emptying in the Mediterranean Sea after forming a vast delta.

All the wrong answers are African capitals (Dakar/Senegal, Addis Ababa/Ethiopia, Nairobi/Kenya).

Answer: Indus

Indus is the Latin name (in turn derived from the Greek "Indos") of the river called Ab-e-sind in Persian and Sindhu in Sanskrit. The country, of course, is India, which borders Pakistan to the east. One of Asia's longest rivers (3,610 km/2,243 mi), the Indus rises in the Tibetan Plateau and flows through northwestern India and Pakistan, ending in a vast delta on the Arabian Sea, not far from the large port city of Karachi.

In the 3rd millennium BC, a major Bronze Age civilization (known as Harappa or Indus Valley Civilization) arose along the course of the river, encompassing much of modern-day Pakistan, western India and northeastern Afghanistan.

Its main centres were the cities of Harappa and Mohenjo-Daro, whose excavations have revealed a surprisingly advanced level of civilization in terms of urban planning, sanitation and technology.

Answer: Papua New Guinea

The island of New Guinea, the second-largest in the world after Greenland, is divided between Indonesia and the independent nation of Papua New Guinea. The Sepik River (1,126 km/700 mi) originates in the central highlands of Papua New Guinea, then winds its way through the north-eastern part of the country until it empties in the Bismarck Sea. Only a minimal part of the river flows through the Indonesian half of the island. Though local populations have been living along the river for thousands of years, the first European contact with the Sepik occurred in 1885, when the Germans were exploring the area as part of establishing the protectorate of German New Guinea.

The remaining answers are all island nations, though only Japan is located in the Pacific (north of the Equator, unlike Papua New Guinea). Madagascar is found in the Indian Ocean, and Haiti in the Atlantic.

Answer: Yangtze

The Three Gorges Dam, the largest power station in the world, spans the Yangtze River near the town of Sandouping, in the central Chinese province of Hubei. The construction of this monumental project, completed in July 2012, caused a lot of controversy in China and abroad, as a number of sites of archaeological and cultural significance were flooded, and over 1 million people were displaced. Though one of the main purpose of the dam was limiting greenhouse gas emissions, the environment of the area where it was built has been affected, with an increasing risk of landslides due to erosion and deforestation. On the positive side, the Three Gorges Dam has vastly improved the danger of seasonal flooding, which in the past affected the highly populated downstream area.

Though the remaining options are all major rivers, they are all considerably shorter than the Yangtze (6,300 km/3,917 mi), which also has the distinction of being the only river to flow entirely within one country. It rises in Tibet and empties in the East China Sea. The huge metropolis of Shanghai, one of the world's busiest ports, is situated in the Yangtze Delta.

Answer: Persian Gulf

The Shatt-el-Arab ("stream of the Arabs"), formed by the confluence of the Tigris and the Euphrates near the town of al-Qurnah in the Basra governorate of southern Iraq, runs for about 200 km (120 mi) through a vast floodplain until it empties in the Persian Gulf, an extension of the Indian Ocean located between Iran and the Arabian peninsula that has often been the focus of international tension. The ancient land of Mesopotamia, one of the cradles of human civilization, lay between those two mighty rivers, which both rise in Turkey. The date palm forest - once much larger - now counts from 3 to 4 million trees. Unfortunately, war, insects and the salinization of the soil have badly damaged the trees, though modern biotechnology might help this unique area to revive.

Of the remaining options, the Bay of Bengal lies east of the Indian subcontinent, the Gulf of Guinea in West Africa, and Botany Bay in southern Australia.

Answer: Romania

The Danube rises in Germany's Black Forest, and winds its way for 2,860 km (1,777 mi) through central and eastern Europe, passing through four capitals (Vienna, Bratislava, Budapest and Belgrade). With a total area of 5,165 km² (1,994 sq mi,), the Danube Delta lies for the most part in northern Romania's Tulcea County; its smaller northern part lies in Ukraine's Odessa Oblast. It is a remote, sparsely-populated area, which, however, has the distinction of being the best-preserved delta in Europe, and one of the most biodiverse regions in the continent. The Delta is a low alluvial plain covered by wetlands and water that harbours a rich wildlife - especially birds, such as the huge great white and Dalmatian pelicans and the mute swan.

While the Danube runs through Hungary (which is landlocked), neither Albania nor Greece are touched by it, being located further south.

Answer: Loire Valley

The castle in question is Amboise, one of the largest and most magnificent of the over 1,000 castles (châteaux in French) that grace France's Loire Valley. It was originally built in the early Middle Ages on a spur overlooking the Loire River. In 1434 it was seized by King Charles VII and transformed into a sumptuous royal palace in the fashionable Italian Renaissance style. Leonardo Da Vinci came to Amboise at the end of 1515 as a guest of Francis I. The great artist lived and worked in the nearby manor of Clos Lucé; when he died in 1521, he was buried in Amboise's Chapel of Saint-Florentin, but his remains were lost after the chapel's destruction. The remains found in the late 19th century and presumed to be Leonardo's are now buried in the Chapel of Saint-Hubert.

The Loire River (1,012 km/629 mi) rises in the Massif Central in southern France, and flows northwest until it empties into the Bay of Biscay. Many historic cities and sites (such as Orléans, Tours and Nantes) are located along the course of the river. The Loire Valley extends for about 208 km (170 mi) along the middle stretch of the river. Known as the Garden of France, it is renowned not only for its rich cultural and artistic heritage, but also for the abundance of vineyards, orchards and other cultivations.

All the wrong answers refer to historical European regions known for their castles. None of them, however, is in France. The Rhineland is in Germany, Alto Adige in northeastern Italy, and Transylvania in Romania.