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 recognised sovereign states, eight cities and islands that are part of non-African states, and two de facto independent states with limited or no recognition. This count does not include Malta and Sicily, which are geologically part of the African continent. Algeria is Africa's largest country by area, and Nigeria is its largest by population. African nations cooperate through the establishment of the African Union, which is headquartered in Addis Ababa.
Africa straddles the equator and the prime meridian. It is the only continent to stretch from the northern temperate to the southern temperate zones.[14] The majority of the continent and its countries are in the Northern Hemisphere, with a substantial portion and a number of countries in the Southern Hemisphere. Most of the continent lies in the tropics, except for a large part of Western Sahara, Algeria, Libya and Egypt, the northern tip of Mauritania, and the entire territories of Morocco, Ceuta, Melilla, and Tunisia which in turn are located above the tropic of Cancer, in the northern temperate zone. In the other extreme of the continent, southern Namibia, southern Botswana, great parts of South Africa, the entire territories of Lesotho and Eswatini and the southern tips of Mozambique and Madagascar are located below the tropic of Capricorn, in the southern temperate zone.