Africa is the second largest of the earth's seven continents, covering about 30,330,000 sq. km (about 11,699,000sq. mi.), including its adjacent islands. It comprises about 22 percent of the world's total land area. In 1990 about 12 percent of the world's population, an estimated 642 million people, lived in Africa, making it the world's second-most populous continent after Asia. Straddling the equator, Africa stretches 8050 km (4970 mi.) from its northernmost point, Ra's al Abya in Tunisia, to its southernmost tip, Cape Agulhas in South Africa.
The maximum width of the continent, measured from the tip of Cap Vert in Senegal, in the west, to Raas Xaafuun (Ras Hafun) in Somalia, in the east, is about 7560 km (about 4700 mi.). The highest point on the continent is the perpetually snowcapped Kilimanjaro (5895 m/19,340 ft) in Tanzania, and the lowest is Lake 'Asal (153 m/502 ft below sea level) in Djibouti. Africa has a regular coastline characterized by few indentations. Its total length is only about 30,490 km (about 18,950 mi.); the length of the African coastline in proportion to its area is less than that of any other continent. The African continent is characterized by plateau land, with a few distinct mountain ranges and a narrow coastal plain. The continent is commonly divided along the lines of the Sahara Desert, the world's largest desert, which cuts a huge swath through the northern half of the continent. The countries north of the Sahara make up the region of North Africa, and include such large and populous nations as Egypt and Algeria.
In general, these nations are more developed than those countries to the south, due in part to the location here of the Nile, the world's longest river. Most of Africa's population lives in the region south of the Sahara, known as sub-Saharan Africa. In this area, eastern Africa includes such countries as Ethiopia, Somalia, and Uganda. Among the nations of Central and West Africa are Angola, Cameroon, Ghana, Nigeria, and the Democratic Republic of the Congo (DRC, formerly Zaire). Southern Africa is dominated by the country of South Africa, and also includes Botswana, Lesotho, and Namibia. Africa also encompasses many islands, the largest of which is Madagascar, located off the southeastern coast of the continent. As a whole, Africa encompasses about 50 nations, ranging from Nigeria, a country of an estimated 127 million people, to small island republics such as Comoros, with a population just over 500,000.
It is widely believed that human life began in Africa sometime between 5 million and 8 million years ago. The continent was home to one of the world's first great civilizations, the Egyptian Empire that was unified more than 5000 years ago. However, foreign colonization and political and ethnic struggles that have hampered industrial and social development have dominated the last 500 years in Africa. The continent remains mostly rural, despite urban growth in the second half of the 20th century. Africa's economy is the least developed of any continent after Antarctica. Agriculture is still the main economic activity. Devastating famine and outbreaks of disease are common, exacerbated by poor roads and the lack of medical personnel.
Africa is rich in natural resources, and part of its economic base is the export of this wealth. Many African nations depend on foreign investment and aid, or on the trade of one or two resources that are subject to market fluctuations. Culturally, Africans are perhaps the most diverse of any continent's inhabitants, with thousands of ethnic groups and more than 1000 different languages. With ethnicity that often cross national boundaries and continual political upheavals, African national identity is not as strong as racial ties or local kin group affiliations. Black Africans make up the majority of the continent's population, but there are also large populations of Arabs, Asians, Europeans, and Berbers. Communities range from rural cultures in which the foods, religions, dress, tribal roles, and daily life have remained unchanged for hundreds of years, to modern city environments, which feature skyscrapers, Western styles of dress and commerce, and a diverse mix of cultural influences.
Music, art, and literature are culturally important and distinctive throughout Africa, and have had considerable impact on other societies around the world. For example, African rhythms have influenced Western popular music styles such as jazz, blues, and rock (see Jazz: Origins). Since the 1950s, most African nations have gained independence from their former colonial powers.
Independence has brought many changes to these nations, including the introduction of multiparty democratic governments and greater efforts to educate their populations. With the world's highest population growth rate, Africa continues to face challenges in its industrial and social development.