Africa is the second-largest continent, and its land is far more varied than many people picture. You met the world's great deserts in Deserts of the World; here they are with Africa's rivers, lakes and highlands.
Key idea
The Sahara, the largest hot desert on Earth, covers the north; the Sahel is the dry grassland on its southern edge. The Nile flows north to the Mediterranean, and the Congo drains the rainforest of the middle. In the east, the Great Rift Valley holds long lakes and volcanoes, including Mount Kilimanjaro (about 5,895 m), Africa's highest peak. Lake Victoria is Africa's largest lake. The Kalahari covers much of the south.
Why it works
Africa's pattern is set by the equator, which crosses its middle. Near the equator it rains most of the year, so rainforest grows in the Congo Basin. Moving north or south from there, the rain comes for only part of the year: savanna grassland. Farther still, around the tropics, dry air sinks and deserts form: the Sahara in the north, the Kalahari and Namib in the south. (See World Climate Zones.)
Worked example: Snow near the equator
Kilimanjaro is only about 3 degrees south of the equator, yet it has snow and ice at the top. Why?
- Air gets colder as you go up, by roughly 6 °C for every 1,000 m.
- Kilimanjaro rises almost 6 km above sea level.
- So its top is far below freezing.
Answer: Because it is so high.
Worked example: Which way does the Nile flow?
The Nile starts in East Africa. Where does it end?
- Its White Nile branch flows out of Lake Victoria; the Blue Nile comes from Ethiopia.
- They join at Khartoum and flow north through Egypt.
- The river ends in a delta on the Mediterranean Sea.
Answer: In the Mediterranean, in Egypt.
Common mistake
People often picture Africa as all desert or all jungle. It has both, and much more: wide savannas (the largest land type in Africa), high plateaus, snowy mountains such as Kilimanjaro, and huge lakes.