10 most difficult con­ti­nents riddles

Data from 2010: South America 350 million, North America 560 million, Europe 720 million, Africa 980 million

Alexander Island was discovered on January 28, 1821 by a Russian expedition under Fabian Gottlieb von Bellingshausen, who named it Alexander I Land for the reigning Tsar Alexander I of Russia. What in fact is an island, was believed to be part of the Antarctic mainland until 1940.

Since North America and Asia had been connected by the Bering land bridge, a number of animal and plant species were able to colonize both continents. Today, similar species are distributed throughout the taiga biome on both continents.

The Bentley Subglacial Trench is a vast topographic trench in Marie Byrd Land, West Antarctica, 80°S, 115°W. At 2,555 meters (8,382 ft) below sea level, it (along with the deepest points within the adjacent Byrd Subglacial Basin) is among the lowest points on the surface of the Earth not covered by ocean, although it is covered by ice.

Bacause of the ongoing spreading of the Atlantic Ocean, Africa and South America (just like Europe and North America) are moving away from each other at the rate of about 3 centimeters (1,2 inch) per year.

This map of Africa is rotated so the continent shape resembles Australia.

The Strait of Gibraltar connects the Atlantic Ocean to the Mediterranean Sea and separates Europe from Africa by 7.7 nautical miles (14.3 km) at the strait's narrowest point. Ferries cross between the two continents every day in as little as 35 minutes.

There is only one such sea - the Mediterranean Sea, which touches Europe, Asia and Africa.

Australia is practically the only developed country not using electricity (indigenous or imported) from nuclear energy. Australia's abundance of cheap coal, conveniently located to population centers, has ruled nuclear energy out of contention on economic grounds. There are nuclear power plants on all other continents, including South America (Brazil, Argentina) and Africa (South Africa).

Three largest continents: Asia (44 million km2), Africa (30 million km2), North America (24 million km2)