Africa is the world's second-largest continent in both area and population, after Asia. At about 30,244,050 km2 (11,677,240 mi2) including its adjacent islands, it covers 20.3 percent of the total land area on Earth, and with over 800 million human inhabitants in 54 countries, it accounts for about one seventh of the world human population.
Separated from Europe by the Mediterranean Sea, it is joined to Asia at its northeast extremity by the Isthmus of Suez, 130 km (80 miles) wide. From the most northerly point, Ras ben Sakka in Tunisia, a little west of Cape Blanc, in 37°21′ N, to the most southerly point, Cape Agulhas in South Africa, 34°51′15″ S, is a distance approximately of 8,000 km (5,000 miles); from Cape Verde, 17°33′22″ W, the westernmost point, to Ras Hafun in Somalia, 51°27′52″ E, the most easterly projection, is a distance (also approximately) of 7,400 km (4,600 miles). The length of coast-line is 26,000 km (16,100 miles) and the absence of deep indentations of the shore is shown by the fact that Europe, which covers only 9,700,000 km2 (3,760,000 square miles), has a coast-line of 32,000 km (19,800 miles).
The main structural lines of the continent show both the east-to-west direction characteristic, at least in the eastern hemisphere, of the more northern parts of the world, and the north-to-south direction seen in the southern peninsulas. Africa is thus composed of two segments at right angles, the northern running from east to west, the southern from north to south, the subordinate lines corresponding in the main to these two directions.