This entry contains a brief description of the topography.

Topic: Afghanistanmostly rugged mountains; plains in north and southwest

Topic: Albaniamostly mountains and hills; small plains along coast

Topic: Algeriamostly high plateau and desert; Atlas Mountains in the far north and Hoggar Mountains in the south; narrow, discontinuous coastal plain

Topic: American Samoafive volcanic islands with rugged peaks and limited coastal plains, two coral atolls (Rose Atoll, Swains Island)

Topic: Andorrarugged mountains dissected by narrow valleys

Topic: Angolanarrow coastal plain rises abruptly to vast interior plateau

Topic: Anguillaflat and low-lying island of coral and limestone

Topic: Antarcticaabout 98% thick continental ice sheet and 2% barren rock, with average elevations between 2,000 and 4,000 m; mountain ranges up to nearly 5,000 m; ice-free coastal areas include parts of southern Victoria Land, Wilkes Land, the Antarctic Peninsula area, and parts of Ross Island on McMurdo Sound; glaciers form ice shelves along about half of the coastline, and floating ice shelves constitute 11% of the area of the continent

Topic: Antigua and Barbudamostly low-lying limestone and coral islands, with some higher volcanic areas

Topic: Arctic Oceancentral surface covered by a perennial drifting polar icepack that, on average, is about 3 m thick, although pressure ridges may be three times that thickness; the icepack is surrounded by open seas during the summer, but more than doubles in size during the winter and extends to the encircling landmasses; the ocean floor is about 50% continental shelf (highest percentage of any ocean) with the remainder a central basin interrupted by three submarine ridges (Alpha Cordillera, Nansen Cordillera, and Lomonosov Ridge) major surface currents: two major, slow-moving, wind-driven currents (drift streams) dominate: a clockwise drift pattern in the Beaufort Gyre in the western part of the Arctic Ocean and a nearly straight line Transpolar Drift Stream that moves eastward across the ocean from the New Siberian Islands (Russia) to the Fram Strait (between Greenland and Svalbard); sea ice that lies close to the center of the gyre can complete a 360 degree circle in about 2 years, while ice on the gyre periphery will complete the same circle in about 7-8 years; sea ice in the Transpolar Drift crosses the ocean in about 3 yearscentral surface covered by a perennial drifting polar icepack that, on average, is about 3 m thick, although pressure ridges may be three times that thickness; the icepack is surrounded by open seas during the summer, but more than doubles in size during the winter and extends to the encircling landmasses; the ocean floor is about 50% continental shelf (highest percentage of any ocean) with the remainder a central basin interrupted by three submarine ridges (Alpha Cordillera, Nansen Cordillera, and Lomonosov Ridge)major surface currents: two major, slow-moving, wind-driven currents (drift streams) dominate: a clockwise drift pattern in the Beaufort Gyre in the western part of the Arctic Ocean and a nearly straight line Transpolar Drift Stream that moves eastward across the ocean from the New Siberian Islands (Russia) to the Fram Strait (between Greenland and Svalbard); sea ice that lies close to the center of the gyre can complete a 360 degree circle in about 2 years, while ice on the gyre periphery will complete the same circle in about 7-8 years; sea ice in the Transpolar Drift crosses the ocean in about 3 years

Topic: Argentinarich plains of the Pampas in northern half, flat to rolling plateau of Patagonia in south, rugged Andes along western border

Topic: ArmeniaArmenian Highland with mountains; little forest land; fast flowing rivers; good soil in Aras River valley

Topic: Arubaflat with a few hills; scant vegetation

Topic: Ashmore and Cartier Islandslow with sand and coral

Topic: Atlantic Oceansurface usually covered with sea ice in Labrador Sea, Denmark Strait, and coastal portions of the Baltic Sea from October to June; surface dominated by two large gyres (broad, circular systems of currents), one in the northern Atlantic and another in the southern Atlantic; the ocean floor is dominated by the Mid-Atlantic Ridge, a rugged north-south centerline for the entire Atlantic basin major surface currents: clockwise North Atlantic Gyre consists of the northward flowing, warm Gulf Stream in the west, the eastward flowing North Atlantic Current in the north, the southward flowing cold Canary Current in the east, and the westward flowing North Equatorial Current in the south; the counterclockwise South Atlantic Gyre composed of the southward flowing warm Brazil Current in the west, the eastward flowing South Atlantic Current in the south, the northward flowing cold Benguela Current in the east, and the westward flowing South Equatorial Current in the northsurface usually covered with sea ice in Labrador Sea, Denmark Strait, and coastal portions of the Baltic Sea from October to June; surface dominated by two large gyres (broad, circular systems of currents), one in the northern Atlantic and another in the southern Atlantic; the ocean floor is dominated by the Mid-Atlantic Ridge, a rugged north-south centerline for the entire Atlantic basinmajor surface currents: clockwise North Atlantic Gyre consists of the northward flowing, warm Gulf Stream in the west, the eastward flowing North Atlantic Current in the north, the southward flowing cold Canary Current in the east, and the westward flowing North Equatorial Current in the south; the counterclockwise South Atlantic Gyre composed of the southward flowing warm Brazil Current in the west, the eastward flowing South Atlantic Current in the south, the northward flowing cold Benguela Current in the east, and the westward flowing South Equatorial Current in the north

Topic: Australiamostly low plateau with deserts; fertile plain in southeast

Topic: Austriamostly mountains (Alps) in the west and south; mostly flat or gently sloping along the eastern and northern margins

Topic: Azerbaijanlarge, flat Kur-Araz Ovaligi (Kura-Araks Lowland, much of it below sea level) with Great Caucasus Mountains to the north, Qarabag Yaylasi (Karabakh Upland) to the west; Baku lies on Abseron Yasaqligi (Apsheron Peninsula) that juts into Caspian Sea

Topic: Bahamas, Thelong, flat coral formations with some low rounded hills

Topic: Bahrainmostly low desert plain rising gently to low central escarpment

Topic: Bangladeshmostly flat alluvial plain; hilly in southeast

Topic: Barbadosrelatively flat; rises gently to central highland region

Topic: Belarusgenerally flat with much marshland

Topic: Belgiumflat coastal plains in northwest, central rolling hills, rugged mountains of Ardennes Forest in southeast

Topic: Belizeflat, swampy coastal plain; low mountains in south

Topic: Beninmostly flat to undulating plain; some hills and low mountains

Topic: Bermudalow hills separated by fertile depressions

Topic: Bhutanmostly mountainous with some fertile valleys and savanna

Topic: Boliviarugged Andes Mountains with a highland plateau (Altiplano), hills, lowland plains of the Amazon Basin

Topic: Bosnia and Herzegovinamountains and valleys

Topic: Botswanapredominantly flat to gently rolling tableland; Kalahari Desert in southwest

Topic: Bouvet Islandvolcanic; coast is mostly inaccessible

Topic: Brazilmostly flat to rolling lowlands in north; some plains, hills, mountains, and narrow coastal belt

Topic: British Indian Ocean Territoryflat and low (most areas do not exceed two m in elevation)

Topic: British Virgin Islandscoral islands relatively flat; volcanic islands steep, hilly

Topic: Bruneiflat coastal plain rises to mountains in east; hilly lowland in west

Topic: Bulgariamostly mountains with lowlands in north and southeast

Topic: Burkina FasoMostly flat to dissected, undulating plains; hills in the west and southeast.  Occupies an extensive plateau with savanna that is grassy in the north and gradually gives way to sparse forests in the south. (2019)

Topic: Burmacentral lowlands ringed by steep, rugged highlands

Topic: Burundihilly and mountainous, dropping to a plateau in east, some plains

Topic: Cabo Verdesteep, rugged, rocky, volcanic

Topic: Cambodiamostly low, flat plains; mountains in southwest and north

Topic: Cameroondiverse, with coastal plain in southwest, dissected plateau in center, mountains in west, plains in north

Topic: Canadamostly plains with mountains in west, lowlands in southeast

Topic: Cayman Islandslow-lying limestone base surrounded by coral reefs

Topic: Central African Republicvast, flat to rolling plateau; scattered hills in northeast and southwest

Topic: Chadbroad, arid plains in center, desert in north, mountains in northwest, lowlands in south

Topic: Chilelow coastal mountains, fertile central valley, rugged Andes in east

Topic: Chinamostly mountains, high plateaus, deserts in west; plains, deltas, and hills in east

Topic: Christmas Islandsteep cliffs along coast rise abruptly to central plateau

Topic: Clipperton Islandcoral atoll

Topic: Cocos (Keeling) Islandsflat, low-lying coral atolls

Topic: Colombiaflat coastal lowlands, central highlands, high Andes Mountains, eastern lowland plains (Llanos)

Topic: Comorosvolcanic islands, interiors vary from steep mountains to low hills

Topic: Congo, Democratic Republic of thevast central basin is a low-lying plateau; mountains in east

Topic: Congo, Republic of thecoastal plain, southern basin, central plateau, northern basin

Topic: Cook Islandslow coral atolls in north; volcanic, hilly islands in south

Topic: Coral Sea Islandssand and coral reefs and islands (cays)

Topic: Costa Ricacoastal plains separated by rugged mountains including over 100 volcanic cones, of which several are major active volcanoes

Topic: Cote d'Ivoiremostly flat to undulating plains; mountains in northwest

Topic: Croatiageographically diverse; flat plains along Hungarian border, low mountains and highlands near Adriatic coastline and islands

Topic: Cubamostly flat to rolling plains, with rugged hills and mountains in the southeast

Topic: Curacaogenerally low, hilly terraingenerally low, hilly terrain

Topic: Cypruscentral plain with mountains to north and south; scattered but significant plains along southern coast

Topic: CzechiaBohemia in the west consists of rolling plains, hills, and plateaus surrounded by low mountains; Moravia in the east consists of very hilly country

Topic: Denmarklow and flat to gently rolling plains

Topic: Djibouticoastal plain and plateau separated by central mountains

Topic: Dominicarugged mountains of volcanic origin

Topic: Dominican Republicrugged highlands and mountains interspersed with fertile valleys

Topic: Ecuadorcoastal plain (costa), inter-Andean central highlands (sierra), and flat to rolling eastern jungle (oriente)

Topic: Egyptvast desert plateau interrupted by Nile valley and delta

Topic: El Salvadormostly mountains with narrow coastal belt and central plateau

Topic: Equatorial Guineacoastal plains rise to interior hills; islands are volcanic

Topic: Eritreadominated by extension of Ethiopian north-south trending highlands, descending on the east to a coastal desert plain, on the northwest to hilly terrain and on the southwest to flat-to-rolling plains

Topic: Estoniamarshy, lowlands; flat in the north, hilly in the south

Topic: Eswatinimostly mountains and hills; some moderately sloping plains

Topic: Ethiopiahigh plateau with central mountain range divided by Great Rift Valley

Topic: European Unionfairly flat along Baltic and Atlantic coasts; mountainous in the central and southern areas

Topic: Falkland Islands (Islas Malvinas)rocky, hilly, mountainous with some boggy, undulating plains

Topic: Faroe Islandsrugged, rocky, some low peaks; cliffs along most of coast

Topic: Fijimostly mountains of volcanic origin

Topic: Finlandmostly low, flat to rolling plains interspersed with lakes and low hills

Topic: Francemetropolitan France: mostly flat plains or gently rolling hills in north and west; remainder is mountainous, especially Pyrenees in south, Alps in east; French Guiana: low-lying coastal plains rising to hills and small mountains; Guadeloupe: Basse-Terre is volcanic in origin with interior mountains; Grande-Terre is low limestone formation; most of the seven other islands are volcanic in origin; Martinique: mountainous with indented coastline; dormant volcano; Mayotte: generally undulating, with deep ravines and ancient volcanic peaks; Reunion: mostly rugged and mountainous; fertile lowlands along coastmetropolitan France: mostly flat plains or gently rolling hills in north and west; remainder is mountainous, especially Pyrenees in south, Alps in east; French Guiana: low-lying coastal plains rising to hills and small mountains; Guadeloupe: Basse-Terre is volcanic in origin with interior mountains; Grande-Terre is low limestone formation; most of the seven other islands are volcanic in origin; Martinique: mountainous with indented coastline; dormant volcano; Mayotte: generally undulating, with deep ravines and ancient volcanic peaks; Reunion: mostly rugged and mountainous; fertile lowlands along coast

Topic: French Polynesiamixture of rugged high islands and low islands with reefs

Topic: French Southern and Antarctic LandsIle Amsterdam (Ile Amsterdam et Ile Saint-Paul): a volcanic island with steep coastal cliffs; the center floor of the volcano is a large plateau; Ile Saint-Paul (Ile Amsterdam et Ile Saint-Paul): triangular in shape, the island is the top of a volcano, rocky with steep cliffs on the eastern side; has active thermal springs; Iles Crozet: a large archipelago formed from the Crozet Plateau is divided into two groups of islands; Iles Kerguelen: the interior of the large island of Ile Kerguelen is composed of high mountains, hills, valleys, and plains with peninsulas stretching off its coasts; Bassas da India (Iles Eparses): atoll, awash at high tide; shallow (15 m) lagoon; Europa Island, Glorioso Islands, Juan de Nova Island: low, flat, and sandy; Tromelin Island (Iles Eparses): low, flat, sandy; likely volcanic seamountIle Amsterdam (Ile Amsterdam et Ile Saint-Paul): a volcanic island with steep coastal cliffs; the center floor of the volcano is a large plateau; Ile Saint-Paul (Ile Amsterdam et Ile Saint-Paul): triangular in shape, the island is the top of a volcano, rocky with steep cliffs on the eastern side; has active thermal springs; Iles Crozet: a large archipelago formed from the Crozet Plateau is divided into two groups of islands; Iles Kerguelen: the interior of the large island of Ile Kerguelen is composed of high mountains, hills, valleys, and plains with peninsulas stretching off its coasts; Bassas da India (Iles Eparses): atoll, awash at high tide; shallow (15 m) lagoon; Europa Island, Glorioso Islands, Juan de Nova Island: low, flat, and sandy; Tromelin Island (Iles Eparses): low, flat, sandy; likely volcanic seamount

Topic: Gabonnarrow coastal plain; hilly interior; savanna in east and south

Topic: Gambia, Theflood plain of the Gambia River flanked by some low hills

Topic: Gaza Stripflat to rolling, sand- and dune-covered coastal plain

Topic: Georgialargely mountainous with Great Caucasus Mountains in the north and Lesser Caucasus Mountains in the south; Kolkhet'is Dablobi (Kolkhida Lowland) opens to the Black Sea in the west; Mtkvari River Basin in the east; fertile soils in river valley flood plains and foothills of Kolkhida Lowland

Topic: Germanylowlands in north, uplands in center, Bavarian Alps in south

Topic: Ghanamostly low plains with dissected plateau in south-central area

Topic: Gibraltara narrow coastal lowland borders the Rock of Gibraltar

Topic: Greecemountainous with ranges extending into the sea as peninsulas or chains of islands

Topic: Greenlandflat to gradually sloping icecap covers all but a narrow, mountainous, barren, rocky coast

Topic: Grenadavolcanic in origin with central mountains

Topic: Guamvolcanic origin, surrounded by coral reefs; relatively flat coralline limestone plateau (source of most fresh water), with steep coastal cliffs and narrow coastal plains in north, low hills in center, mountains in south

Topic: Guatemalatwo east-west trending mountain chains divide the country into three regions: the mountainous highlands, the Pacific coast south of mountains, and the vast northern Peten lowlands

Topic: Guernseymostly flat with low hills in southwest

Topic: Guineagenerally flat coastal plain, hilly to mountainous interior

Topic: Guinea-Bissaumostly low-lying coastal plain with a deeply indented estuarine coastline rising to savanna in east; numerous off-shore islands including the Arquipelago Dos Bijagos consisting of 18 main islands and many small islets

Topic: Guyanamostly rolling highlands; low coastal plain; savanna in south

Topic: Haitimostly rough and mountainous

Topic: Heard Island and McDonald IslandsHeard Island - 80% ice-covered, bleak and mountainous, dominated by a large massif (Big Ben) and an active volcano (Mawson Peak); McDonald Islands - small and rocky

Topic: Holy See (Vatican City)urban; low hill

Topic: Hondurasmostly mountains in interior, narrow coastal plains

Topic: Hong Konghilly to mountainous with steep slopes; lowlands in north

Topic: Hungarymostly flat to rolling plains; hills and low mountains on the Slovakian border

Topic: Icelandmostly plateau interspersed with mountain peaks, icefields; coast deeply indented by bays and fiords

Topic: Indiaupland plain (Deccan Plateau) in south, flat to rolling plain along the Ganges, deserts in west, Himalayas in north

Topic: Indian Oceansurface dominated by a major gyre (broad, circular system of currents) in the southern Indian Ocean and a unique reversal of surface currents in the northern Indian Ocean; ocean floor is dominated by the Mid-Indian Ocean Ridge and subdivided by the Southeast Indian Ocean Ridge, Southwest Indian Ocean Ridge, and Ninetyeast Ridge major surface currents: the counterclockwise Indian Ocean Gyre comprised of the southward flowing warm Agulhas and East Madagascar Currents in the west, the eastward flowing South Indian Current in the south, the northward flowing cold West Australian Current in the east, and the westward flowing South Equatorial Current in the north; a distinctive annual reversal of surface currents occurs in the northern Indian Ocean; low atmospheric pressure over southwest Asia from hot, rising, summer air results in the southwest monsoon and southwest-to-northeast winds and clockwise currents, while high pressure over northern Asia from cold, falling, winter air results in the northeast monsoon and northeast-to-southwest winds and counterclockwise currentssurface dominated by a major gyre (broad, circular system of currents) in the southern Indian Ocean and a unique reversal of surface currents in the northern Indian Ocean; ocean floor is dominated by the Mid-Indian Ocean Ridge and subdivided by the Southeast Indian Ocean Ridge, Southwest Indian Ocean Ridge, and Ninetyeast Ridgemajor surface currents: the counterclockwise Indian Ocean Gyre comprised of the southward flowing warm Agulhas and East Madagascar Currents in the west, the eastward flowing South Indian Current in the south, the northward flowing cold West Australian Current in the east, and the westward flowing South Equatorial Current in the north; a distinctive annual reversal of surface currents occurs in the northern Indian Ocean; low atmospheric pressure over southwest Asia from hot, rising, summer air results in the southwest monsoon and southwest-to-northeast winds and clockwise currents, while high pressure over northern Asia from cold, falling, winter air results in the northeast monsoon and northeast-to-southwest winds and counterclockwise currents

Topic: Indonesiamostly coastal lowlands; larger islands have interior mountains

Topic: Iranrugged, mountainous rim; high, central basin with deserts, mountains; small, discontinuous plains along both coasts

Topic: Iraqmostly broad plains; reedy marshes along Iranian border in south with large flooded areas; mountains along borders with Iran and Turkey

Topic: Irelandmostly flat to rolling interior plain surrounded by rugged hills and low mountains; sea cliffs on west coast

Topic: Isle of Manhills in north and south bisected by central valley

Topic: IsraelNegev desert in the south; low coastal plain; central mountains; Jordan Rift Valley

Topic: Italymostly rugged and mountainous; some plains, coastal lowlands

Topic: Jamaicamostly mountains, with narrow, discontinuous coastal plain

Topic: Jan Mayenvolcanic island, partly covered by glaciers

Topic: Japanmostly rugged and mountainous

Topic: Jerseygently rolling plain with low, rugged hills along north coast

Topic: Jordanmostly arid desert plateau; a great north-south geological rift along the west of the country is the dominant topographical feature and includes the Jordan River Valley, the Dead Sea, and the Jordanian Highlands

Topic: Kazakhstanvast flat steppe extending from the Volga in the west to the Altai Mountains in the east and from the plains of western Siberia in the north to oases and deserts of Central Asia in the south

Topic: Kenyalow plains rise to central highlands bisected by Great Rift Valley; fertile plateau in west

Topic: Kiribatimostly low-lying coral atolls surrounded by extensive reefs

Topic: Korea, Northmostly hills and mountains separated by deep, narrow valleys; wide coastal plains in west, discontinuous in east

Topic: Korea, Southmostly hills and mountains; wide coastal plains in west and south

Topic: Kosovoflat fluvial basin at an elevation of 400-700 m above sea level surrounded by several high mountain ranges with elevations of 2,000 to 2,500 m

Topic: Kuwaitflat to slightly undulating desert plain

Topic: Kyrgyzstanpeaks of the Tien Shan mountain range and associated valleys and basins encompass the entire country

Topic: Laosmostly rugged mountains; some plains and plateaus

Topic: Latvialow plain

Topic: Lebanonnarrow coastal plain; El Beqaa (Bekaa Valley) separates Lebanon and Anti-Lebanon Mountains

Topic: Lesothomostly highland with plateaus, hills, and mountains

Topic: Liberiamostly flat to rolling coastal plains rising to rolling plateau and low mountains in northeast

Topic: Libyamostly barren, flat to undulating plains, plateaus, depressions

Topic: Liechtensteinmostly mountainous (Alps) with Rhine Valley in western third

Topic: Lithuanialowland, many scattered small lakes, fertile soil

Topic: Luxembourgmostly gently rolling uplands with broad, shallow valleys; uplands to slightly mountainous in the north; steep slope down to Moselle flood plain in the southeast

Topic: Macaugenerally flat

Topic: Madagascarnarrow coastal plain, high plateau and mountains in center

Topic: Malawinarrow elongated plateau with rolling plains, rounded hills, some mountains

Topic: Malaysiacoastal plains rising to hills and mountains

Topic: Maldivesflat, with white sandy beaches

Topic: Malimostly flat to rolling northern plains covered by sand; savanna in south, rugged hills in northeast

Topic: Maltamostly low, rocky, flat to dissected plains; many coastal cliffs

Topic: Marshall Islandslow coral limestone and sand islands

Topic: Mauritaniamostly barren, flat plains of the Sahara; some central hills

Topic: Mauritiussmall coastal plain rising to discontinuous mountains encircling central plateau

Topic: Mexicohigh, rugged mountains; low coastal plains; high plateaus; desert

Topic: Micronesia, Federated States ofislands vary geologically from high mountainous islands to low, coral atolls; volcanic outcroppings on Pohnpei, Kosrae, and Chuuk

Topic: Moldovarolling steppe, gradual slope south to Black Sea

Topic: Monacohilly, rugged, rocky

Topic: Mongoliavast semidesert and desert plains, grassy steppe, mountains in west and southwest; Gobi Desert in south-central

Topic: Montenegrohighly indented coastline with narrow coastal plain backed by rugged high limestone mountains and plateaus

Topic: Montserratvolcanic island, mostly mountainous, with small coastal lowland

Topic: Moroccomountainous northern coast (Rif Mountains) and interior (Atlas Mountains) bordered by large plateaus with intermontane valleys, and fertile coastal plains; the south is mostly low, flat desert with large areas of rocky or sandy surfaces 

Topic: Mozambiquemostly coastal lowlands, uplands in center, high plateaus in northwest, mountains in west

Topic: Namibiamostly high plateau; Namib Desert along coast; Kalahari Desert in east

Topic: Naurusandy beach rises to fertile ring around raised coral reefs with phosphate plateau in center

Topic: Navassa Islandraised flat to undulating coral and limestone plateau; ringed by vertical white cliffs (9 to 15 m high)

Topic: NepalTarai or flat river plain of the Ganges in south; central hill region with rugged Himalayas in north

Topic: Netherlandsmostly coastal lowland and reclaimed land (polders); some hills in southeast

Topic: New Caledoniacoastal plains with interior mountains

Topic: New Zealandpredominately mountainous with large coastal plains

Topic: Nicaraguaextensive Atlantic coastal plains rising to central interior mountains; narrow Pacific coastal plain interrupted by volcanoes

Topic: Nigerpredominately desert plains and sand dunes; flat to rolling plains in south; hills in north

Topic: Nigeriasouthern lowlands merge into central hills and plateaus; mountains in southeast, plains in north

Topic: Niuesteep limestone cliffs along coast, central plateau

Topic: Norfolk Islandvolcanic island with mostly rolling plains

Topic: North Macedoniamountainous with deep basins and valleys; three large lakes, each divided by a frontier line; country bisected by the Vardar River

Topic: Northern Mariana Islandsthe southern islands in this north-south trending archipelago are limestone, with fringing coral reefs; the northern islands are volcanic, with active volcanoes on several islands

Topic: Norwayglaciated; mostly high plateaus and rugged mountains broken by fertile valleys; small, scattered plains; coastline deeply indented by fjords; arctic tundra in north

Topic: Omancentral desert plain, rugged mountains in north and south

Topic: Pacific Oceansurface dominated by two large gyres (broad, circular systems of currents), one in the northern Pacific and another in the southern Pacific; in the northern Pacific, sea ice forms in the Bering Sea and Sea of Okhotsk in winter; in the southern Pacific, sea ice from Antarctica reaches its northernmost extent in October; the ocean floor in the eastern Pacific is dominated by the East Pacific Rise, while the western Pacific is dissected by deep trenches, including the Mariana Trench, which is the world's deepest at 10,924 m major surface currents: clockwise North Pacific Gyre formed by the warm northward flowing Kuroshio Current in the west, the eastward flowing North Pacific Current in the north, the southward flowing cold California Current in the east, and the westward flowing North Equatorial Current in the south; the counterclockwise South Pacific Gyre composed of the southward flowing warm East Australian Current in the west, the eastward flowing South Pacific Current in the south, the northward flowing cold Peru (Humbolt) Current in the east, and the westward flowing South Equatorial Current in the northsurface dominated by two large gyres (broad, circular systems of currents), one in the northern Pacific and another in the southern Pacific; in the northern Pacific, sea ice forms in the Bering Sea and Sea of Okhotsk in winter; in the southern Pacific, sea ice from Antarctica reaches its northernmost extent in October; the ocean floor in the eastern Pacific is dominated by the East Pacific Rise, while the western Pacific is dissected by deep trenches, including the Mariana Trench, which is the world's deepest at 10,924 mmajor surface currents: clockwise North Pacific Gyre formed by the warm northward flowing Kuroshio Current in the west, the eastward flowing North Pacific Current in the north, the southward flowing cold California Current in the east, and the westward flowing North Equatorial Current in the south; the counterclockwise South Pacific Gyre composed of the southward flowing warm East Australian Current in the west, the eastward flowing South Pacific Current in the south, the northward flowing cold Peru (Humbolt) Current in the east, and the westward flowing South Equatorial Current in the north

Topic: Pakistandivided into three major geographic areas: the northern highlands, the Indus River plain in the center and east, and the Balochistan Plateau in the south and west

Topic: Palauvarying topography from the high, mountainous main island of Babelthuap to low, coral islands usually fringed by large barrier reefs

Topic: Panamainterior mostly steep, rugged mountains with dissected, upland plains; coastal plains with rolling hills

Topic: Papua New Guineamostly mountains with coastal lowlands and rolling foothills

Topic: Paracel Islandsmostly low and flat

Topic: Paraguaygrassy plains and wooded hills east of Rio Paraguay; Gran Chaco region west of Rio Paraguay mostly low, marshy plain near the river, and dry forest and thorny scrub elsewhere

Topic: Peruwestern coastal plain (costa), high and rugged Andes in center (sierra), eastern lowland jungle of Amazon Basin (selva)

Topic: Philippinesmostly mountains with narrow to extensive coastal lowlands

Topic: Pitcairn Islandsrugged volcanic formation; rocky coastline with cliffs

Topic: Polandmostly flat plain; mountains along southern border

Topic: Portugalthe west-flowing Tagus River divides the country: the north is mountainous toward the interior, while the south is characterized by rolling plains

Topic: Puerto Ricomostly mountains with coastal plain in north; precipitous mountains to the sea on west coast; sandy beaches along most coastal areas

Topic: Qatarmostly flat and barren desert

Topic: Romaniacentral Transylvanian Basin is separated from the Moldavian Plateau on the east by the Eastern Carpathian Mountains and separated from the Walachian Plain on the south by the Transylvanian Alps

Topic: Russiabroad plain with low hills west of Urals; vast coniferous forest and tundra in Siberia; uplands and mountains along southern border regions

Topic: Rwandamostly grassy uplands and hills; relief is mountainous with altitude declining from west to east

Topic: Saint Barthelemyhilly, almost completely surrounded by shallow-water reefs, with plentiful beaches

Topic: Saint Helena, Ascension, and Tristan da Cunhathe islands of this group are of volcanic origin associated with the Atlantic Mid-Ocean RidgeSaint Helena: rugged, volcanic; small scattered plateaus and plains; Ascension: surface covered by lava flows and cinder cones of 44 dormant volcanoes; terrain rises to the east; Tristan da Cunha: sheer cliffs line the coastline of the nearly circular island; the flanks of the central volcanic peak are deeply dissected; narrow coastal plain lies between The Peak and the coastal cliffsthe islands of this group are of volcanic origin associated with the Atlantic Mid-Ocean RidgeSaint Helena: rugged, volcanic; small scattered plateaus and plains; Ascension: surface covered by lava flows and cinder cones of 44 dormant volcanoes; terrain rises to the east; Tristan da Cunha: sheer cliffs line the coastline of the nearly circular island; the flanks of the central volcanic peak are deeply dissected; narrow coastal plain lies between The Peak and the coastal cliffs

Topic: Saint Kitts and Nevisvolcanic with mountainous interiors

Topic: Saint Luciavolcanic and mountainous with broad, fertile valleys

Topic: Saint Pierre and Miquelonmostly barren rock

Topic: Saint Vincent and the Grenadinesvolcanic, mountainous

Topic: Samoatwo main islands (Savaii, Upolu) and several smaller islands and uninhabited islets; narrow coastal plain with volcanic, rugged mountains in interior

Topic: San Marinorugged mountains

Topic: Sao Tome and Principevolcanic, mountainous

Topic: Saudi Arabiamostly sandy desert

Topic: Senegalgenerally low, rolling, plains rising to foothills in southeast

Topic: Serbiaextremely varied; to the north, rich fertile plains; to the east, limestone ranges and basins; to the southeast, ancient mountains and hills

Topic: SeychellesMahe Group is volcanic with a narrow coastal strip and rocky, hilly interior; others are coral, flat, elevated reefs

Topic: Sierra Leonecoastal belt of mangrove swamps, wooded hill country, upland plateau, mountains in east

Topic: Singaporelowlying, gently undulating central plateau

Topic: Sint Maartenlow, hilly terrain, volcanic originlow, hilly terrain, volcanic origin

Topic: Slovakiarugged mountains in the central and northern part and lowlands in the south

Topic: Sloveniaa short southwestern coastal strip of Karst topography on the Adriatic; an alpine mountain region lies adjacent to Italy and Austria in the north; mixed mountains and valleys with numerous rivers to the east

Topic: Solomon Islandsmostly rugged mountains with some low coral atolls

Topic: Somaliamostly flat to undulating plateau rising to hills in north

Topic: South Africavast interior plateau rimmed by rugged hills and narrow coastal plain

Topic: South Georgia and South Sandwich Islandsmost of the islands are rugged and mountainous rising steeply from the sea; South Georgia is largely barren with steep, glacier-covered mountains; the South Sandwich Islands are of volcanic origin with some active volcanoes

Topic: South Sudanplains in the north and center rise to southern highlands along the border with Uganda and Kenya; the White Nile, flowing north out of the uplands of Central Africa, is the major geographic feature of the country; The Sudd (a name derived from floating vegetation that hinders navigation) is a large swampy area of more than 100,000 sq km fed by the waters of the White Nile that dominates the center of the country

Topic: Southern Oceanthe Southern Ocean is 4,000 to 5,000-m deep over most of its extent with only limited areas of shallow water; the Antarctic continental shelf is generally narrow and unusually deep, its edge lying at depths of 400 to 800 m (the global mean is 133 m); the Antarctic icepack grows from an average minimum of 2.6 million sq km in March to about 18.8 million sq km in September, better than a sixfold increase in area major surface currents: the cold, clockwise-flowing Antarctic Circumpolar Current (West Wind Drift; 21,000 km long) moves perpetually eastward around the continent and is the world's largest and strongest ocean current, transporting 130 million cubic meters of water per second - 100 times the flow of all the world's rivers; it is also the only current that flows all the way around the planet and connects the Atlantic, Pacific, and Indian Oceans; the cold Antarctic Coastal Current (East Wind Drift) is the southernmost current in the world, flowing westward and parallel to the Antarctic coastlinethe Southern Ocean is 4,000 to 5,000-m deep over most of its extent with only limited areas of shallow water; the Antarctic continental shelf is generally narrow and unusually deep, its edge lying at depths of 400 to 800 m (the global mean is 133 m); the Antarctic icepack grows from an average minimum of 2.6 million sq km in March to about 18.8 million sq km in September, better than a sixfold increase in areamajor surface currents: the cold, clockwise-flowing Antarctic Circumpolar Current (West Wind Drift; 21,000 km long) moves perpetually eastward around the continent and is the world's largest and strongest ocean current, transporting 130 million cubic meters of water per second - 100 times the flow of all the world's rivers; it is also the only current that flows all the way around the planet and connects the Atlantic, Pacific, and Indian Oceans; the cold Antarctic Coastal Current (East Wind Drift) is the southernmost current in the world, flowing westward and parallel to the Antarctic coastline

Topic: Spainlarge, flat to dissected plateau surrounded by rugged hills; Pyrenees Mountains in north

Topic: Spratly Islandssmall, flat islands, islets, cays, and reefs

Topic: Sri Lankamostly low, flat to rolling plain; mountains in south-central interior

Topic: Sudangenerally flat, featureless plain; desert dominates the north

Topic: Surinamemostly rolling hills; narrow coastal plain with swamps

Topic: Svalbardrugged mountains; much of the upland areas are ice covered; west coast clear of ice about half the year; fjords along west and north coasts

Topic: Swedenmostly flat or gently rolling lowlands; mountains in west

Topic: Switzerlandmostly mountains (Alps in south, Jura in northwest) with a central plateau of rolling hills, plains, and large lakes

Topic: Syriaprimarily semiarid and desert plateau; narrow coastal plain; mountains in west

Topic: Taiwaneastern two-thirds mostly rugged mountains; flat to gently rolling plains in west

Topic: Tajikistanmountainous region dominated by the Alay Mountains in the north and the Pamirs in the southeast; western Fergana Valley in north, Kofirnihon and Vakhsh Valleys in southwest

Topic: Tanzaniaplains along coast; central plateau; highlands in north, south

Topic: Thailandcentral plain; Khorat Plateau in the east; mountains elsewhere

Topic: Timor-Lestemountainous

Topic: Togogently rolling savanna in north; central hills; southern plateau; low coastal plain with extensive lagoons and marshes

Topic: Tokelaulow-lying coral atolls enclosing large lagoons

Topic: Tongamostly flat islands with limestone bedrock formed from uplifted coral formation; others have limestone overlying volcanic rock

Topic: Trinidad and Tobagomostly plains with some hills and low mountains

Topic: Tunisiamountains in north; hot, dry central plain; semiarid south merges into the Sahara

Topic: Turkeyhigh central plateau (Anatolia); narrow coastal plain; several mountain ranges

Topic: Turkmenistanflat-to-rolling sandy desert with dunes rising to mountains in the south; low mountains along border with Iran; borders Caspian Sea in west

Topic: Turks and Caicos Islandslow, flat limestone; extensive marshes and mangrove swamps

Topic: Tuvalulow-lying and narrow coral atolls

Topic: Ugandamostly plateau with rim of mountains

Topic: Ukrainemostly fertile plains (steppes) and plateaus, with mountains found only in the west (the Carpathians) or in the extreme south of the Crimean Peninsula

Topic: United Arab Emiratesflat, barren coastal plain merging into rolling sand dunes of vast desert; mountains in east

Topic: United Kingdommostly rugged hills and low mountains; level to rolling plains in east and southeast

Topic: United Statesvast central plain, mountains in west, hills and low mountains in east; rugged mountains and broad river valleys in Alaska; rugged, volcanic topography in Hawaii

Topic: United States Pacific Island Wildlife Refugeslow and nearly flat sandy coral islands with narrow fringing reefs that have developed at the top of submerged volcanic mountains, which in most cases rise steeply from the ocean floor

Topic: Uruguaymostly rolling plains and low hills; fertile coastal lowland

Topic: Uzbekistanmostly flat-to-rolling sandy desert with dunes; broad, flat intensely irrigated river valleys along course of Amu Darya, Syr Darya (Sirdaryo), and Zaravshan; Fergana Valley in east surrounded by mountainous Tajikistan and Kyrgyzstan; shrinking Aral Sea in west

Topic: Vanuatumostly mountainous islands of volcanic origin; narrow coastal plains

Topic: VenezuelaAndes Mountains and Maracaibo Lowlands in northwest; central plains (llanos); Guiana Highlands in southeast

Topic: Vietnamlow, flat delta in south and north; central highlands; hilly, mountainous in far north and northwest

Topic: Virgin Islandsmostly hilly to rugged and mountainous with little flat land

Topic: Wake Islandatoll of three low coral islands, Peale, Wake, and Wilkes, built up on an underwater volcano; central lagoon is former crater, islands are part of the rim

Topic: Wallis and Futunavolcanic origin; low hills

Topic: West Bankmostly rugged, dissected upland in west, flat plains descending to Jordan River Valley to the east

Topic: Worldtremendous variation of terrain on each of the continents; check the World 'Elevation' entry for a compilation of terrain extremes; the world's ocean floors are marked by mid-ocean ridges while the ocean surfaces form a dynamic, continuously changing environment; check the 'Terrain' field and its 'major surface currents' and 'ocean zones' subfields under each of the five ocean (Arctic, Atlantic, Indian, Pacific, and Southern) entries for further information on oceanic environs

Ten Cave Superlatives: compiled from "Geography - note(s)" under various country entries where more details may be found

largest cave: Son Doong in Phong Nha-Ke Bang National Park, Vietnam is the world's largest cave (greatest cross sectional area) and is the largest known cave passage in the world by volume; it currently measures a total of 38.5 million cu m (about 1.35 billion cu ft); it connects to Thung cave (but not yet officially); when recognized, it will add an additional 1.6 million cu m in volume

largest ice cave: the Eisriesenwelt (Ice Giants World) inside the Hochkogel mountain near Werfen, Austria is the world's largest and longest ice cave system at 42 km (26 mi) 

longest cave: Mammoth Cave, in west-central Kentucky, is the world's longest known cave system with more than 650 km (405 mi) of surveyed passageways

longest salt cave: the Malham Cave in Mount Sodom in Israel is the world's longest salt cave at 10 km (6 mi); its survey is not complete and its length will undoubtedly increase

longest underwater cave: the Sac Actun cave system in Mexico at 348 km (216 mi) is the longest underwater cave in the world and the second longest cave worldwide

longest lava tube cave: Kazumura Cave on the island of Hawaii is the world's longest and deepest lava tube cave; it has been surveyed at 66 km (41 mi) long and 1,102 m (3,614 ft) deep 

deepest cave: Veryovkina Cave in the Caucasus country of Georgia is the world's deepest cave, plunging down 2,212 m (7,257 ft)

deepest underwater cave: the Hranice Abyss in Czechia is the world's deepest surveyed underwater cave at 404 m (1,325 ft); its survey is not complete and it could end up being some 800-1,200 m deep

largest cave chamber: the Miao Room in the Gebihe cave system at China's Ziyun Getu He Chuandong National Park encloses some 10.78 million cu m (380.7 million cu ft) of volume

largest bat cave: Bracken Cave outside of San Antonio, Texas is the world's largest bat cave; it is the summer home to the largest colony of bats in the world; an estimated 20 million Mexican free-tailed bats roost in the cave from March to October making it the world's largest known concentration of mammals

Topic: Yemennarrow coastal plain backed by flat-topped hills and rugged mountains; dissected upland desert plains in center slope into the desert interior of the Arabian Peninsula

Topic: Zambiamostly high plateau with some hills and mountains

Topic: Zimbabwemostly high plateau with higher central plateau (high veld); mountains in east