AfricaAfrica is the world's second-largest and second-most populous continent, after Asia in both aspects. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surface area. With billion people as of , it accounts for about of the world's human population. Africa's population is the youngest amongst all the continents; the median age in 2012 was 19.7, when the worldwide median age was 30.4.
Urban planningUrban planning, also known as town planning, city planning, regional planning, or rural planning, is a technical and political process that is focused on the development and design of land use and the built environment, including air, water, and the infrastructure passing into and out of urban areas, such as transportation, communications, and distribution networks and their accessibility.
Sub-Saharan AfricaSub-Saharan Africa, Subsahara, or Non-Mediterranean Africa, is the area and regions of the continent of Africa that lie south of the Sahara. These include Central Africa, East Africa, Southern Africa, and West Africa. Geopolitically, in addition to the African countries and territories that are situated fully in that specified region, the term may also include polities that only have part of their territory located in that region, per the definition of the United Nations (UN).
Slavery in AfricaSlavery has historically been widespread in Africa. Systems of servitude and slavery were common in parts of Africa in ancient times, as they were in much of the rest of the ancient world. When the trans-Saharan slave trade, Indian Ocean slave trade and Atlantic slave trade (which started in the 16th century) began, many of the pre-existing local African slave systems began supplying captives for slave markets outside Africa. Slavery in contemporary Africa is still practiced despite it being illegal.
Urban sprawlUrban sprawl (also known as suburban sprawl or urban encroachment) is defined as "the spreading of urban developments (such as houses and shopping centers) on undeveloped land near a city". Urban sprawl has been described as the unrestricted growth in many urban areas of housing, commercial development, and roads over large expanses of land, with little concern for urban planning. In addition to describing a special form of urbanization, the term also relates to the social and environmental consequences associated with this development.
