I'm actually surprised with the number of people saying that "Africa didn't do anything" line. They forget the first rule of history: the winners write it.
Europe (and its descendents) rule the world today. I'm not saying that's a good thing, but I'm not saying it's a bad thing, it's just the truth. It should be no surprise, then, that even Jesus -- a man who was born somewhere between classical Egypt and Syria -- is shown on the cross with long, straight blonde hair and blue eyes in some places. These are the same people who forget the scientific progress in the Near East while Europe was living through its dark ages, or the 1.3 billion people living in the world's longest-standing continuous Civilization.
At any rate, 3 African Civilizations, plus Egypt (4) would probably be a good number. Zulu, Abyssinia, and Mali would round the continent out quite well. This would compare quite well with the Inca/Maya/Aztec trinity of South America.