Antarctica

The second smallest continent, mostly south of the Antarctic Circle.

Area: 14.2 million sq. km (5.5 million sq. mi.).

Geographic South Pole: Earth's southernmost point, at latitude 90°S, where all lines of longitude meet.

Magnetic South Pole: The magnetic South Pole shifts about 5 miles (km) a year and is now located at about 66°S and 139°E on the Adélie Coast of Antarctica.

Terrain: About 98% thick ice sheet and 2% barren rock; glaciers form ice shelves along about half of the coastline, and floating ice shelves constitute 11% of the area of the continent. Ice sheet: The continental ice sheet contains approximately 7 million cubic miles (30 million cu km) of ice, representing about 90% of the world's total. Major ice shelves: Amery, Filchner, Larsen, Ronne, Ross. Ice shelves make up about 10% of Antarctica's ice, and are floating sheets of ice attached to land that project out into coastal waters.

Climate: The coldest, windiest, driest continent.

Regions: East Antarctica (c. 3,000,000 sq. mi./7,770,000 sq. km), the largest portion of the continent, is a high, ice-covered plateau. West Antarctica (c. 2,500,000 sq. mi./6,475,000 sq. km), is an archipelago of mountainous islands connected by ice. A mountain range divides them.

Elevation extremes: Lowest point: Bentley Subglacial Trench –8,327 ft. below sea level (–2,538 m)—the lowest land elevation is hidden within the trench. Highest point: Vinson Massif 16,066 ft. (4,897 m), Ellsworth Mountains.

The Arctic

Region, primarily made up of the frozen Arctic Ocean, that surrounds the North Pole. Land masses include islands and the northern parts of the European, Asian, and North American continents.

Area: 14.056 million sq. km (5.4 million sq. mi.), largely frozen ocean.

Geographic North Pole: Northern end of Earth's axis, located at about latitude 90°N.

Magnetic North Pole: Continues to shift and is located at approximately 82°N and 114°W in the Queen Elizabeth Islands of northern Canada.

Terrain: Central surface covered by a perennial drifting polar icepack that averages about 3 meters in 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.

Climate: Polar climate characterized by persistent cold and relatively narrow annual temperature ranges; winters characterized by continuous darkness, cold and stable weather conditions, and clear skies; summers characterized by continuous daylight, damp and foggy weather, and weak cyclones with rain or snow.

Regions: The Arctic is divided by the summer isotherm, a climatic boundary between regions with summer temperatures averaging 50°F (or 10°C)—the subarctic—and colder regions (the true Arctic).

Elevation extremes: Lowest point: Fram Basin –4,665 m. Highest point: sea level 0 m.