Some parts of Africa had plenty of water, but others never had enough water. Some places had enough water in good years but not in bad years. The amount of water made a big difference to how the scenery looked, and also to how many people and animals could live there. People needed a lot of water to grow their crops so they could eat. A lot of bad droughts in a row could have made a mighty kingdom collapse.
In most of Africa, the rain came from the same place as the Indian monsoon, off the Indian Ocean. When there was a good year, lots of rain came. Most of the rain fell in East Africa and in the rain forests of central Africa. Water from the rain filled up the streams, and the streams came together to make rivers, and the rivers flowed into places where it hardly ever rained, like Egypt, and brought water there for farming.
But in a bad year, it doesn't rain much, and hardly any water comes down the rivers. Then no food grows, and there are terrible famines along the rivers.
Some parts of Africa never get much water. The Sahara Desert runs in a wide belt across the northern part of Africa. There are a few people and plants there, but not very many because there is almost no water.
In North Africa, north of the Sahara along the Mediterranean Sea, there is usually enough water for farming, but not always. People are always worried about water, and try to save water as much as they can. South of the Sahara, in East Africa, there was not enough water for farming, but the land did grow great stretches of grassland, like American prairies. The people who...