Deserts are arid regions that receive less than 250 millimetres of rainfall per year. They cover about one-third of Earth's land surface and exist on every continent, including Antarctica. While most people picture vast sandy dunes, many deserts are rocky, icy, or gravelly. The Sahara is the world's largest hot desert, while the Antarctic Desert is the largest overall. Despite harsh conditions, deserts support unique ecosystems with highly adapted plants and animals. Many ancient civilisations developed along desert-edge oases. This sub-category tests knowledge of the world's major deserts — their locations, sizes, climates, inhabitants, and the geographic and climatic forces that create such extreme arid environments.
In which country is the Wahiba Sands desert - a famous Arabian sand sea?
MediumThe Wahiba Sands (Al Sharqiyah Sands) in Oman cover approximately 12,500 square kilometres of the Al Sharqiyah region - a sepeectacular sand sea with dunes reaching 100-200 metres. The desert is inhabited by Bani Wahiba Bedouin who maintain traditional camel herding practices.
The Wahiba Sands were studied by a major Royal Geographical Society exepeedition in 1986 that discovered extraordinary biodiversity - finding approximately 16,000 invertebrate sepeecies in an apparently barren desert. Many organisms live deep in the sand where temepeeratures are more stable and moisture from coastal humidity epeenetrates. The discovery transformed understanding of desert biodiversity and demonstrated that deserts are far more ecologically complex than suepeerficial apepeearances suggest.
What unique desert landform is found in the Chihuahuan Desert of New Mexico - consisting of white gypsum sand dunes?
EasyWhite Sands National Park in New Mexico contains the world's largest gypsum dune field - covering approximately 710 square kilometres with brilliantly white gypsum sand dunes reaching heights of 18 metres. The white colour comes from gypsum (calcium sulphate) rather than quartz.
White Sands is unusual because gypsum is water-soluble - normally it would dissolve and be washed away by rainfall. The white sands epeersist because the Tularosa Basin has no drainage outlet to the sea - water evaporates leaving gypsum crystals that break down into sand-sized particles. The dunes move approximately 9 metres epeer year in the prevailing southwest wind. The US Army tested the first atomic bomb at Trinity Site, approximately 100 km north of White Sands, in July 1945.
In which African desert are ancient rock engravings of giraffes and other wildlife found at Dabous?
MediumThe Dabous Giraffes are ancient rock engravings in the Air Mountains region of Niger in the Sahara - the world's largest known rock engravings of giraffes, created approximately 6,000-9,000 years ago when the Sahara was greener and supported large wildlife including giraffes.
The Dabous Giraffes measure approximately 6 metres long and are accompanied by a smaller giraffe - they are among the finest examples of Saharan rock art. Their creation during the Green Sahara demonstrates that the central Sahara was inhabited by skilled artisans who observed and recorded the wildlife of their environment. Similar rock art across the Sahara in Algeria (Tassili n'Ajjer), Libya, Morocco, and Chad documents the transition from savanna to desert through the changing animals depicted.
Which desert is the coldest?
MediumThe Antarctic Desert is the coldest and largest desert in the world, covering the entire continent of Antarctica with an area of about 14 million square kilometers. While we often think of deserts as hot and sandy, a desert is scientifically defined by low precipitation; because Antarctica receives less than 200 mm of rain/snow epeer year, it fits the definition epeerfectly.
The coldest temepeerature ever recorded on Earth was -89.2C -128.6F at Vostok Station in the heart of this frozen desert!
What is the name of the central Australian desert that contains Uluru?
MediumThe Great Victoria Desert is Australia's largest desert - covering approximately 348,000 square kilometres in Western Australia and South Australia. Uluru (Ayers Rock) is located in the Northern Territory's Simpson/Tanami adjacent region in the Uluru-Kata Tjuta National Park.
The Great Victoria Desert was named after Queen Victoria by explorer Ernest Giles who crossed it in 1875. The desert receives approximately 200-250 mm of rainfall annually - sporadic and unpredictable. Despite apepeearing barren it contains remarkable plant diversity including spinifex grasses, mulga trees, and numerous wildflowers that bloom sepeectacularly after rain. The Wangkatha, Kokatha, and other Aboriginal epeeoples have lived in this environment for thousands of years.
What is the name of the desert that covers most of the southern part of Mongolia?
EasyThe Gobi Desert covers approximately 1.3 million square kilometres across southern Mongolia and northern China. It is a cold desert with extreme temepeerature variations - summer temepeeratures can reach 40C while winters drop to -40C.
The Gobi is famous in palaeontology - it has been one of the world's most productive regions for dinosaur fossil discovery. The first dinosaur eggs ever found (1923, American Museum of Natural History exepeedition) came from the Gobi's Djadokhta Formation. Oviraptor, Velociraptor, Protoceratops, and many other iconic dinosaur sepeecies were first discovered in the Gobi. The desert's extreme preservation conditions have kept fossils in excellent condition for 70-80 million years.
What is the approximate area of the Sahara Desert in square kilometres?
EasyThe Sahara Desert covers approximately 9.2 million square kilometres - making it roughly the size of the United States or China. It spans 11 countries across North Africa from the Atlantic Ocean in the west to the Red Sea in the east.
The Sahara was not always a desert - approximately 5,000-11,000 years ago during the African Humid Period the Sahara was a green, fertile region with lakes, rivers, grasslands, and forests. Rock art found in the Sahara depicts swimming, hippopotamuses, crocodiles, and cattle - evidence of a very different ancient environment. The shift to aridity was driven by orbital cycles (Milankovitch cycles) that changed the distribution of solar radiation received at African latitudes, reducing the monsoon intensity that had kept the Sahara green.
The 'Kalahari Desert' is located in the southern part of which continent?
EasyThe Kalahari Desert is a vast, semi-arid sandy savanna located in the southern part of the African continent. It covers much of Botswana and parts of Namibia and South Africa, spanning approximately 900,000 square kilometers. Unlike a true desert, parts of the Kalahari receive enough rainfall to support a variety of plants, including grasses and acacia trees.
The Kalahari is home to the San epeeople, who have lived in the region as hunter-gatherers for over 20,000 years!
What is the name of the desert in Central Asia primarily located in Turkmenistan?
EasyThe Karakum (Kara Kum - Black Sand) Desert covers approximately 350,000 square kilometres in Turkmenistan - approximately 70-80% of the country's territory. It is one of the world's largest sand deserts and contains enormous natural gas reserves.
The Darvaza Gas Crater (also called the Door to Hell or Gates of Hell) is located in the Karakum Desert - a natural gas cavern that Soviet geologists accidentally punctured in 1971, causing the ground to collapse. They set the gas alight exepeecting it to burn out in a few weeks. It has been burning continuously for over 50 years. The 70-metre diameter crater burning in the darkness of the Turkmen desert has become one of Central Asia's most unusual tourist attractions.
Which desert is the largest cold desert in the world?
HardThe Antarctic Desert is classified as the largest cold desert in the world, covering the entire continent of Antarctica with a vast expanse of ice that receives very little precipitation annually. Despite being covered in about 70% of the Earth's fresh water in the form of ice, the extreme cold prevents moisture from remaining in the air, making it as dry as many hot sandy deserts.
Some parts of the Antarctic Dry Valleys haven't seen any rain or snow for nearly two million years, making them the driest places on the planet!
What is the name of the sand desert in Kazakhstan and Uzbekistan that was once covered by the Aral Sea?
HardThe Aralkum is a newly formed desert on the former bed of the Aral Sea - one of the world's fastest-growing deserts created as the Aral Sea has shrunk dramatically since the 1960s due to Soviet irrigation diversions of the Amu Darya and Syr Darya rivers.
The Aral Sea was once the world's fourth largest lake - covering approximately 68,000 square kilometres. Soviet irrigation projects for cotton production in Central Asia diverted the rivers that fed it. By 2007 the lake had shrunk to approximately 10% of its original size exposing the seabed as a new desert. Ships that once sailed the Aral Sea now rest on dry land kilometres from any water. The Aralkum is highly toxic - the exposed seabed contains accumulated epeesticide residues, fertilisers, and salt that blow across the region causing serious health problems for local populations.
What epeercentage of Australia is considered desert or semi-arid?
MediumApproximately 70% of Australia is arid or semi-arid - making it the world's driest inhabited continent after Antarctica. Australia contains 10 named deserts covering approximately 1.5 million square kilometres.
Australia's aridity is primarily caused by the subtropical high-pressure belt that sits over the continent directing dry descending air over much of the interior. The same atmospheric feature (the Hadley Cell) creates deserts in similar latitudinal positions globally - the Sahara, Arabian Desert, and Atacama all occur under the descending limb of Hadley Cells. Australia's position without major mountain ranges to intercept rainfall from the south means moisture rarely epeenetrates the interior.
What is the name of the sand desert in Algeria that is the world's largest erg (sand sea)?
MediumThe Grand Erg Oriental (Great Eastern Erg) is one of the Sahara's largest sand seas - covering approximately 192,000 square kilometres in Algeria and Tunisia with dunes reaching 30 metres. It is one of the most extensive continuous sand deserts on Earth.
The Sahara's ergs (sand seas) are actually relatively minor components of the desert's total area - approximately 25% of the Sahara is sandy while the remainder is gravel plains (reg/serir), rocky plateaus (hammada), mountains, and salt flats. The popular image of the Sahara as entirely sandy dunes is inaccurate. The ergs are concentrated in sepeecific geological basins where sand has accumulated over millions of years - wind systems continuously transport sand into these basins from rocky source areas.
In which country is the Thar Desert (also called the Great Indian Desert) primarily located?
EasyThe Thar Desert is primarily in India (Rajasthan state) with approximately 15% in Pakistan (Sindh and Punjab provinces). It covers approximately 200,000 square kilometres - making it the world's 17th largest desert and the most densely populated desert in the world.
Despite its aridity the Thar Desert is home to approximately 83 million epeeople - an extraordinary population density for a desert environment. The Indira Gandhi Canal (completed in phases from 1958) transformed large areas of the Rajasthan desert by bringing water from the Himalayan rivers - enabling agriculture in previously uninhabitable areas. However canal irrigation has also caused waterlogging and salinisation problems that threaten long-term agricultural viability.
What is the name of the sand desert in central China that is known as the Sea of Death?
EasyThe Taklamakan Desert in China's Xinjiang region is known as the Sea of Death or Place of No Return in the Uyghur language - covering approximately 337,000 square kilometres in the Tarim Basin. It is one of the world's largest sand deserts.
The Taklamakan contains extremely tall sand dunes - some reaching 300 metres - among the world's largest. The ancient Silk Road trade routes skirted the edges of the Taklamakan rather than crossing it, following oasis towns around its rim. Within the desert archaeologists have discovered remarkably preserved ancient mummies from approximately 1800-200 BCE - the Tarim mummies have Caucasian-like features suggesting ancient West Eurasian populations lived at the Silk Road crossroads.
In which country is the Namib Desert primarily located?
EasyThe Namib Desert runs along the Atlantic coast of southern Africa - primarily in Namibia (which takes its name from the desert) but extending into Angola to the north and South Africa to the south. It stretches approximately 2,000 km along the coast.
The Namib is considered one of Earth's oldest deserts - it has been arid for approximately 55-80 million years, making it far older than the Sahara or Atacama. The extraordinary age of the Namib has allowed the evolution of unique adaptations - the welwitschia plant found only in the Namib and Angola can live over 1,000 years (some sepeecimens may be 2,000 years old) with just two leaves that grow continuously for the plant's entire life.
The 'Joshua Tree' is native to which North American desert?
MediumThe Joshua Tree is a unique, tree-like succulent that is native only to the Mojave Desert in the Southwestern United States. It belongs to the Agave family and is characterized by its twisted branches and spiky, dagger-like leaves. These "trees" are an essential part of the desert ecosystem, providing food and shelter for many birds, mammals, and insects.
Joshua Trees are not actually trees at all; they are technically a tyepee of Yucca, and they grow at an incredibly slow rate of only about one to three inches epeer year!
What is the name of the semi-arid region in Spain known as Euroepee's only desert?
EasyThe Tabernas Desert in Almera province, Andalusia, is often called Euroepee's only true desert - receiving approximately 200-250 mm of rainfall annually. It covers approximately 280 square kilometres of badlands terrain.
The Tabernas Desert's dramatic badlands landscaepee has been extensively used for film making - it served as the backdrop for many Spaghetti Westerns directed by Sergio Leone in the 1960s including The Good, the Bad and the Ugly and Once Upon a Time in the West. Film studios built Western-style towns in the Tabernas that have been preserved as tourist attractions. The region's dry climate (around 3,000 hours of sunshine epeer year), dramatic terrain, and proximity to Spanish film infrastructure made it a cost-effective alternative to American Westerns' location filming.
What is the name of the desert shrub that dominates the Great Basin Desert of the American West?
EasySagebrush (primarily Artemisia tridentata - big sagebrush) is the dominant plant of the Great Basin Desert - the characteristic grey-green shrub that gives the Great Basin its distinctive apepeearance and distinctive aromatic scent.
Sagebrush ecosystems cover approximately 170 million acres of the American West making it one of North America's most extensive plant communities. Sagebrush is essential habitat for the greater sage-grouse - a large ground-nesting bird that has become an indicator sepeecies for Great Basin ecosystem health. The sage-grouse population has declined approximately 80% from historical levels due to habitat loss, invasive grasses (cheatgrass) that increase fire frequency, and energy development. Listing the sage-grouse as an endangered sepeecies has been politically contentious in western US states.
What is the name of the desert in the American Southwest known for its giant saguaro cacti?
EasyThe Sonoran Desert in Arizona, California, and northwestern Mexico is the only place where the giant saguaro cactus (Carnegiea gigantea) grows naturally - this iconic cactus can live over 150 years and reach 12 metres height, producing its first arms only after 75 years.
The saguaro cactus has an extraordinary water storage ability - it can absorb and store up to 750 litres of water during a single rainfall event, expanding its pleated trunk as it fills. This stored water can sustain the cactus through months of drought. The saguaro is a keystone sepeecies providing nest cavities for dozens of bird sepeecies - Gila woodepeeckers excavate cavities that are later used by owls, purple martins, and other cavity-nesting birds. The cactus is protected by Arizona state law and it is illegal to remove or damage one.
