Africa: Sahara, savannah and the Nile

Africa has the largest hot desert in the world: the Sahara, where temperatures range from 30°C to 46°C, rain stays below 25 cm, and there are hardly any plants.

But look at how life copes:

• The fennec fox's large ears do two jobs at once: they let heat escape, and they listen for prey underground.
• Cacti store water in their leaves.
• Date palms grow together at oases (an oasis is a place with water and plants in an otherwise dry desert), giving dates rich in carbohydrates, vitamins and minerals.

People adapted too. Nomads' traditional clothes and headgear are designed to keep the body cool, and underground homes stay cool in summer and warm in winter.

The Sahara has long been home to nomadic tribes herding sheep, goats and camels, and to trade. Ancient routes crossed it carrying gold, salt, and ideas to the Mediterranean world.

South of the desert lies the savannah: a tropical grassland with wide open spaces, scattered trees and seasonal rain, lying between the rainforests and the deserts.

Its clear wet and dry seasons shape everything: plant growth, and the migration of elephants, lions, zebras and giraffes that depend on its grasses and waterholes. Farming, deforestation and climate change now threaten that balance.

And Africa has the longest river in the world: the Nile, almost 6,650 km long.

The Nile and its basin were the cradle of ancient Egyptian civilisation. For thousands of years its water has turned dry land into fertile fields growing wheat, barley, flax, fruit and vegetables, while also giving drinking water, fishing, hydroelectric power and a transport route.