Africa is the world’s second largest and second most-populous continent, being behind Asia in both categories. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth’s total surface area and 20% of its land area. With 1.2 billion people as of 2016, it accounts for about 16% of the world’s human population. The continent is surrounded by the Mediterranean Sea to the north, the Isthmus of Suez and the Red Sea to the northeast, the Indian Ocean to the southeast and the Atlantic Ocean to the west. The continent includes Madagascar and various archipelagos. It contains 54 fully recognized sovereign states (countries), nine territories and two defacto independent states with limited or no recognition. The majority of the continent and its countries are in the Northern Hemisphere, with a substantial portion and number of countries in the Southern Hemisphere.
Africa’s average population is the youngest amongst all the continents; the median age in 2012 was 19.7, when the worldwide median age was 30.4. Algeria is Africa’s largest country by area, and Nigeria is its largest by population. Africa straddles the equator and encompasses numerous climate areas; it is the only continent to stretch from the northern temperate to southern temperate zones.