Africa is the world's second largest and second most-populous continent, after Asia. At about 30,221,532 km² (11,668,545 mi²) including adjacent islands, it covers 6.0% of the Earth's total surface area, and 20.4% of the total land area.Sayre, April Pulley. (1999) Africa, Twenty-First Century Books. ISBN 0-7613-1367-2.