Geography.

Bhutan has the highest average elevation of any country, about 3,280 m above sea level, ahead of Nepal (about 3,265 m) and Tajikistan (about 3,186 m).

Mount Kosciuszko in the Snowy Mountains of New South Wales rises 2,228 m, making it the highest mountain on the Australian mainland.

Algeria, covering 2,381,741 km², has been the largest country in Africa since the 2011 breakup of Sudan; it is also the largest country of the Mediterranean basin and the tenth largest in the world.

Brazil, with a total area of about 8,515,767 km² according to the Brazilian Institute of Geography and Statistics (IBGE), is the largest country in South America and the fifth-largest country in the world.

Borneo, shared by Indonesia, Malaysia and Brunei, covers about 743,330 km², making it the largest island in Asia and the third-largest island in the world after Greenland and New Guinea.

Great Britain, with an area of 209,331 km², is the largest island in Europe and the largest of the British Isles, and the ninth-largest island in the world.

Lake Ladoga in north-western Russia, near Saint Petersburg, has an average surface area of about 17,891 km² (excluding islands), making it the largest lake located entirely in Europe.

The Ganges–Brahmaputra Delta (Ganges Delta), lying mostly in Bangladesh and the Indian state of West Bengal, covers more than 105,000 km² and is the largest river delta in the world.

The Murray River, which flows 2,508 km from the Australian Alps to the Southern Ocean in South Australia, is Australia's longest river.

Ethiopia, landlocked since Eritrea's independence in 1993, is the most populous landlocked country in the world with about 138 million inhabitants as of 2026, making it also Africa's second most populous country.

Sistema Ox Bel Ha in Quintana Roo, Mexico, has about 541.7 km of surveyed underwater passages (CINDAQ 2025 report) — the longest explored underwater cave in the world, ahead of nearby Sistema Sac Actun (about 380 km). Exploration is ongoing, so the figure grows each year.

India overtook China as the world's most populous country in 2023, with a population estimated at approximately 1.44 billion as of 2024, according to United Nations projections — a milestone that had been anticipated for years given the two countries' diverging population growth trends.

Kazakhstan covers about 2,724,900 km² — the ninth-largest country in the world and the largest landlocked country, bordering the (landlocked) Caspian Sea but with no access to the open ocean.

Mongolia has about 3.4 million people spread over roughly 1.56 million km² — around 2.2 people per km², the lowest population density of any sovereign country. Nearly half of the population lives in the capital, Ulaanbaatar.

Chile stretches about 4,270 km from its border with Peru to Cape Horn while averaging only about 177 km wide — the longest country from north to south in the world, spanning climates from the Atacama Desert to subantarctic fjords.

The Maldives, a chain of about 1,190 coral islands in the Indian Ocean, has an average ground elevation of only about 1.5 m above sea level and a natural high point of just a few metres — the lowest-lying country on Earth and among the most vulnerable to sea-level rise.

Monaco has about 38,000 residents on roughly 2.08 km² of land on the French Riviera — around 19,000 people per km², the highest population density of any sovereign country. Its area has grown slightly over the decades through land reclamation from the sea.

Wellington, New Zealand, at about 41°17′S (41.29°S), is the southernmost national capital in the world, located on the southern tip of the North Island beside Cook Strait.

Puncak Jaya (Carstensz Pyramid) in the Indonesian province of Central Papua on New Guinea rises to 4,884 m — the highest island peak in the world and the highest point in Oceania, one of the Seven Summits. It carries some of the last remaining tropical glaciers.

Lake Titicaca on the border of Peru and Bolivia lies at about 3,812 m above sea level and is commonly described as the highest navigable lake in the world, plied by passenger and cargo ships since the 19th century. It is also South America's largest lake by volume.

Aconcagua in Mendoza Province, Argentina, rises to about 6,961 m — the highest mountain in the Americas, in both the Western and Southern Hemispheres, and anywhere outside Asia.

Mount Elbrus, a dormant volcano in the Caucasus of southern Russia, rises to about 5,642 m at its western summit and is conventionally considered the highest mountain in Europe. If the Caucasus is excluded, Mont Blanc (about 4,806 m) holds the title.

Gangkhar Puensum on the Bhutan–China border rises to about 7,570 m and is widely considered the highest unclimbed mountain in the world. Several attempts in the 1980s failed, and Bhutan banned climbing peaks above 6,000 m in 1994 and later all mountaineering out of respect for local spiritual beliefs.

The Amazon basin drains about 7 million km² across Brazil, Peru, Bolivia, Colombia, Ecuador, Venezuela and Guyana — nearly 40% of South America and the largest drainage basin on Earth. Estimates vary between about 6.1 and 7.05 million km² depending on whether the Tocantins basin is included.

Thanks to overseas territories scattered across every ocean — including French Polynesia, New Caledonia and the French Southern and Antarctic Lands — France has the world's largest exclusive economic zone, about 10.9 million km², just ahead of the United States. Published totals range from about 10.2 to 11.7 million km² depending on the treatment of disputed and extended areas.

Lake Superior, shared by Canada and the United States, covers about 82,100 km² — the largest freshwater lake in the world by surface area and the largest of North America's Great Lakes, holding about 10% of the world's surface fresh water.

The Tibetan Plateau covers roughly 2.5 million km² with an average elevation above 4,500 m — the largest and highest plateau on Earth, often called 'the Roof of the World'. Its glaciers feed major rivers including the Yangtze, Yellow, Indus, Brahmaputra and Mekong.

Eisriesenwelt ('World of the Ice Giants') in the Tennengebirge near Werfen, Austria, is about 42 km long — the largest ice cave in the world — with ice formations covering roughly the first kilometre of passages, which is the part open to visitors.

Samosir, in Lake Toba on the Indonesian island of Sumatra, covers about 630 km² — roughly the size of Singapore — and is home to over 100,000 Batak people. It is the largest island within a lake on an island anywhere in the world.

Lake Volta in Ghana, formed behind the Akosombo Dam after its completion in 1965, covers about 8,502 km² — roughly 3.6% of Ghana's land area and the largest artificial lake in the world by surface area.

The Amazon discharges an average of roughly 209,000 m³ of water per second into the Atlantic Ocean — about one-fifth of all river water reaching the world's oceans and more than the next seven largest rivers combined.

Bananal Island in the state of Tocantins, Brazil, formed where the Araguaia River splits into two branches, covers about 19,162 km² — the largest fluvial island in the world. (Marajó, at the Amazon mouth, is larger but is bordered by the Atlantic and is not a purely fluvial island.)

Lake Van in eastern Türkiye covers about 3,755 km² and has a pH of around 9.7–9.8 — the largest soda lake in the world and the largest lake in Türkiye. It has no outlet, and its endemic microbialites form some of the tallest known.

Lake Victoria, shared by Uganda, Kenya and Tanzania, covers roughly 68,800 km² — the largest lake in Africa, the largest tropical lake in the world and the second-largest freshwater lake by area after Lake Superior. It is the principal reservoir of the White Nile.

The Greater Tokyo Area, including Tokyo and its surrounding prefectures, has a metropolitan population of approximately 37 million people — the largest urban agglomeration in the world by population, per United Nations urbanization data.

Lake Toba in North Sumatra, Indonesia, covers about 1,130 km² and fills the caldera of the supervolcano whose eruption roughly 74,000 years ago was the largest of the Quaternary — making it the largest volcanic lake on Earth.

Mammoth Cave in Kentucky, USA, has over 686 km of mapped passages — the longest known cave system in the world, more than three times longer than the second-longest, and new passages continue to be discovered and surveyed regularly.

Lake Tanganyika in the East African Rift stretches about 673 km from north to south, bordered by Tanzania, the Democratic Republic of the Congo, Burundi and Zambia — the longest freshwater lake in the world, and also the second-deepest and second-oldest.

The Shanghai Metro spans approximately 831 km of route length across its network — the longest metro system in the world, having expanded rapidly since its first line opened in 1995 to become the busiest and most extensive urban rail network on Earth.

The Volga flows about 3,530 km from the Valdai Hills northwest of Moscow to the Caspian Sea, draining much of western Russia — the longest river in Europe.

The Yangtze (Chang Jiang) flows about 6,300 km from the Tibetan Plateau to the East China Sea near Shanghai entirely within China — the longest river in Asia, the third-longest in the world, and the longest to flow within a single country.

Baku, Azerbaijan, on the western shore of the Caspian Sea, lies about 28 m below sea level — the lowest national capital in the world and the largest city located below sea level.

Jericho, in the Jordan Valley of the West Bank, lies about 258 m below sea level — the lowest city on Earth — and is also considered one of the oldest continuously inhabited settlements, with remains dating back more than 10,000 years.

Kaffeklubben Island, off the north coast of Peary Land in Greenland, reaches about 83°39′45″N (83.66°N) and is the northernmost permanent land on Earth, about 707 km from the North Pole. Several gravel bars reported farther north are transient and shift or disappear.

The Danube flows about 2,850 km from Germany's Black Forest to the Black Sea, passing through or along the borders of 10 countries — Germany, Austria, Slovakia, Hungary, Croatia, Serbia, Romania, Bulgaria, Moldova and Ukraine — more than any other river. It also passes through four national capitals.

The border between Morocco and Peñón de Vélez de la Gomera — a rocky Spanish exclave on the Mediterranean coast connected to the mainland by a sandy isthmus formed in 1934 — is only about 85 m long, the shortest international land border in the world.

The Khone Phapheng Falls on the Mekong River in southern Laos, near the Cambodian border, stretch about 10,783 m across a maze of channels and islands — the widest waterfall in the world according to Guinness World Records.

Murmansk, Russia, at about 68.97°N on the Kola Peninsula, had about 270,000 residents at the 2021 Russian census — the largest city north of the Arctic Circle, home to an ice-free port warmed by the North Atlantic Current. Its population has declined steadily since the Soviet era.

The Hranice Abyss (Hranická propast) in the Czech Republic is the deepest known flooded cave: a remotely operated vehicle reached 404 m in 2016 without touching bottom, and the UX1-Neo robot reached about 450 m in 2022. Geophysical surveys suggest the abyss may extend to around 1 km.

Gaet'ale Pond, a small hypersaline pool in Ethiopia's Danakil Depression, was measured in a 2022 scientific study at a salinity of roughly 433 g/L (about 43% dissolved salt by weight) — surpassing Antarctica's Don Juan Pond (previously considered the saltiest natural body of water) to become the saltiest known natural body of water on Earth. Despite the extreme salinity and near-boiling surface temperatures nearby, researchers found evidence of microbial life adapted to the pond's harsh chemistry.