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, particularly central Eastern Africa, is widely accepted as the place of origin of humans and the Hominidae clade (great apes), as evidenced by the discovery of the earliest hominids and their ancestors as well as later ones that have been dated to around 7 million years ago, including Sahelanthropus tchadensis, Australopithecus africanus, A. afarensis, Homo erectus, H. habilis and H. ergaster—the earliest Homo sapiens (modern human), found in Ethiopia, date to circa 200,000 years ago. Africa straddles the equator and encompasses numerous climate areas; it is the only continent to stretch from the northern temperate to southern temperate zones.
Africa hosts a large diversity of ethnicities, cultures and languages. In the late 19th century, European countries colonised almost all of Africa; most present states in Africa originated from a process of decolonisation in the 20th century. African nations cooperate through the establishment of the African Union, which is headquartered in Addis Ababa.
Afri was a Latin name used to refer to the inhabitants of Africa, which in its widest sense referred to all lands south of the Mediterranean (Ancient Libya). This name seems to have originally referred to a native Libyan tribe; see Terence for discussion. The name is usually connected with Hebrew or Phoenician ʿafar 'dust', but a 1981 hypothesis has asserted that it stems from the Berber ifri (plural ifran) "cave", in reference to cave dwellers. The same word may be found in the name of the Banu Ifran from Algeria and Tripolitania, a Berber tribe originally from Yafran (also known as Ifrane) in northwestern Libya.
Under Roman rule, Carthage became the capital of the province of Africa Proconsularis, which also included the coastal part of modern Libya. The Latin suffix -ica can sometimes be used to denote a land (e.g., in Celtica from Celtae, as used by Julius Caesar). The later Muslim kingdom of Ifriqiya, located in modern-day Tunisia, also preserved a form of the name.
According to the Romans, Africa lay to the west of Egypt, while "Asia" was used to refer to Anatolia and lands to the east. A definite line was drawn between the two continents by the geographer Ptolemy (85–165 AD), indicating Alexandria along the Prime Meridian and making the isthmus of Suez and the Red Sea the boundary between Asia and Africa. As Europeans came to understand the real extent of the continent, the idea of "Africa" expanded with their knowledge.