This river trivia quiz has 50 free questions with answers and covers the great rivers of every continent: the Nile and the Amazon and their argument over which is longest, the Yangtze and its record-breaking dam, the Mississippi and its Ojibwe name, the Congo and its 220-metre depths, the Danube through ten countries and four capitals, the Thames, the Ganges, the Volga, the Zambezi and the Mekong. It also collects the oddities: the river Guinness once crowned the world's shortest, the river in Antarctica that flows away from the sea, the American river that caught fire and helped create the EPA, the river Chicago made run backwards, and the western river that rarely reaches the ocean any more. Difficulty runs from easy schoolroom geography to genuinely hard, and every question shows its level. Every answer has been checked against a primary reference and each question carries its citation.
30 of 50 questions with answers and explanations. Play the quiz
Q 01Which two rivers are locked in a long-running dispute over the title of world's longest?
The Nile and the Amazon
The Nile is traditionally listed at about 6,650 km, but some scientists measure the Amazon as longer if you count it to the Pará estuary.
Q 02Which river is the longest in Asia and the longest anywhere to flow entirely within one country?
Yangtze
Its Chinese name, Chang Jiang, simply means Long River. Its delta produces as much as a fifth of China's GDP.
Q 03By discharge volume, which river is by far the largest in the world?
Amazon
It carries about a fifth of all river water reaching the oceans, more than the next seven rivers combined, and pushes fresh water more than 100 km out into the Atlantic.
Q 04How many bridges cross the world's biggest river by volume along its entire South American course?
None
Most of it runs through rainforest with few roads to connect, and in the wet season it can be 48 km wide.
Q 05Which Spanish explorer navigated and named South America's greatest river in 1542?
Francisco de Orellana
He reported being attacked by female fighters. The river rises at Mismi Peak in the Peruvian Andes and crosses Peru, Colombia and Brazil.
Q 06What is the pororoca?
A tidal bore on the Amazon
Ocean tides push a wave far up the river, and surfers have ridden it for miles.
Q 07In which direction does the Nile flow?
North
It empties into the Mediterranean, which is why maps of ancient Egypt put 'Upper Egypt' in the south. Its basin covers eleven countries.
Q 08In which capital city do the White Nile and Blue Nile meet?
Khartoum
The Blue Nile rises near Lake Tana in Ethiopia and, with the Atbarah, supplies 97% of the river's sediment.
Q 09What is the name of the huge reservoir created by Egypt's Aswan High Dam?
Lake Nasser
Before the dam, the annual flood deposited nutrient-rich silt on the banks, the foundation of ancient Egyptian farming.
Q 10Which river is the deepest in the world, with measured depths of around 220 metres?
Congo
It is also the only major river to cross the equator twice, and it was known as the Zaire River for part of the 20th century.
Q 11Which unusual geographic feat does the Congo River perform?
It crosses the equator twice
Its great arc through central Africa takes it north over the line and back south again. Livingstone Falls block ships from reaching the sea.
Q 12How many countries does the Danube run through or border, more than any other river?
Ten
From the Black Forest to the Black Sea it also passes four capitals: Vienna, Bratislava, Budapest and Belgrade.
Q 13In which German region does the Danube rise?
The Black Forest
It is Europe's second-longest river after the Volga at 2,850 km, of which 2,415 km are navigable. It once marked the frontier of the Roman Empire.
Q 21What did engineers do to the Chicago River in 1900?
Reversed its flow away from Lake Michigan
The Sanitary and Ship Canal sent the city's sewage toward the Mississippi instead of its drinking water. Every St Patrick's Day it is dyed green with 40 pounds of vegetable dye.
Q 22How long is Montana's Roe River, which Guinness named the world's shortest river in 1989?
201 feet
Fifth-graders campaigned for the title. Oregon's D River, the previous holder, fought back with a new measurement, and Guinness eventually dropped the category.
Q 23What is the Onyx, at 32 km, notable for?
Q 14Which of these capital cities does NOT sit on the Danube?
Prague
Prague is on the Vltava. Bratislava is the fourth Danube capital.
Q 15Which river is the longest in Europe?
Volga
At about 3,530 km it rises in the Valdai Hills and ends in the Caspian Sea, 28 metres below sea level. Russians call it Mother Volga.
Q 16Into which body of water does the Volga empty?
The Caspian Sea
Its delta is the largest estuary in Europe and the only place in Russia where you can find pelicans, flamingos and lotuses.
Q 17What is the traditional source of the Mississippi River?
Lake Itasca, Minnesota
From there it runs 2,340 miles to the Gulf of Mexico. Its watershed drains parts of 32 states and two Canadian provinces.
Q 18The name Mississippi comes from an Ojibwe phrase meaning what?
Great river
Misi-ziibi, rendered by the French as Misi zipi. 'Father of Waters' and 'Old Man River' are nicknames rather than translations.
Q 19Which river is the longest in the United States, edging out the Mississippi?
Missouri
Together the Mississippi-Missouri system stretches about 6,275 km, the fourth-longest river system on Earth.
Q 20Which river's 1969 fire in Cleveland helped spur the Clean Water Act and the creation of the EPA?
The Cuyahoga
It had burned at least a dozen times since 1868. Time magazine wrote that it 'oozes rather than flows', and Randy Newman wrote a song about it.
It is the longest river in Antarctica
It is a summer meltwater stream that flows away from the ocean into Lake Vanda, has no fish, and in some years never reaches the lake at all.
Q 24Which river carved the Grand Canyon?
Colorado
Its name is Spanish for 'coloured reddish', after its silt. Because of water use it has rarely reached the sea since the 1960s, though it supplies 40 million people.
Q 25Which dam created Lake Mead on the river that carved the Grand Canyon?
Hoover Dam
Glen Canyon Dam upstream formed Lake Powell. Together they hold back a river 1,450 miles long.
Q 26Which river runs the largest hydroelectric power station in the world?
Yangtze
The Three Gorges Dam. The river's basin is home to nearly a third of China's population, and its baiji dolphin was declared extinct in 2006.
Q 27Which Chinese waterway is nicknamed both 'China's Pride' and 'China's Sorrow' for its floods?
Yellow River
Its 1887 and 1931 floods each killed at least a million people. It is the most sediment-laden river in the world, and its bed now sits metres above the surrounding land in places.
Q 28China's second-longest river gets its colour and name from silt from which upland region?
The Loess Plateau
At 5,464 km it is China's second-longest river and empties into the Bohai Sea after crossing nine provinces.
Q 29Which river is the most sacred to Hindus and is worshipped as a goddess?
Ganges
It rises in the Himalayas of Uttarakhand and, with the Brahmaputra, builds the world's largest delta, about 64,000 square kilometres in the Sundarbans.
Q 30Which river system forms the largest delta in the world?
Ganges-Brahmaputra
The Ganges Delta covers about 64,000 square kilometres across Bangladesh and India and includes the Sundarbans mangroves.