Until enormous deserts, and deadly diseases had foiled

Until the 19th century most of Africa was a mystery to the western world.Its impassable forests, rivers blocked by falls, enormous deserts, and deadly diseases had foiled explorers' attempts to infiltrate the interior. Little was known about the hundreds of different groups of people who lived south of the Sahara in communities ranging from small villages to sprawling kingdoms.Nor was it guessed that some four million years ago our earliest ancestors took theirfirst upright steps in Africa's heartland.Africa, as well as being the home of the lion elephant, the tall Watusi and diminutive Pygmy, the longest river and largest dessert, was also the birthplace of humanity.
Africa is a huge continent, second in size only to Asia, but it has few of the other geographical features found on other continents.Its coastline has a relatively small number of inlets and peninsulas.Most of the continent consists of a vast high plateau that drops steeply to narrow coastal plains.Few mountains regions mark Africa and those that do, like the Atlas in the northwest, are relatively small ranges or are isolated volcanic mountains, such as Mount Kilimanjaro. In addition, Africa's major rivers follow very irregular courses.Africa's unique geological history explains these features.
On a map of the world, Africa's West coast and South Americas east coast look as though they could fit together. That is because they once did. About 200 million years ago, the continents were part of a supercontinent called Pangaea. Africa lay in the southern most part called Gondwana. About 180 million years ago Gondwana broke away from Pangaea.Latter continent size chunks of land broke away from Gondwana and drifted away on tectonic plates. Some pieces collided with other plates and crumpled along their edges, forming long mountain chains. The African plate moved much slower than the others did, so it has no collision caused ran…