Well, do remember that Africa is three times the size of Europe. You might get better answers if you divide it up into parts. I'm not an Afrologist, but an example:

• West Africa had Ghana, Mali, Songhay, the Fulani states in the north, and to the south there were Benin, Asanteman, Oyo, Nri, and other powerful kingdoms and cities
• East Africa had Ethiopia and the lavish cities of the Indian Ocean coast
• South Africa historically had many Shona empires, such as Mopata or Zimbabwe
• Central Africa had the celebrated Kingdom of Kongo, besides there were many more, comparatively obscure kingdoms inland into the Congo River Basin

Egypt was a major African Empire before Rome. Or do you mean Sub-Saharan Africa.

If you want to learn about some African empires other than the mainstream Egyptian ones, I would suggest looking into the empire of Songhai and the Sultanate of Mali. Those were two interesting sub-saharan African powers of the time, and there are stories of great wealth flowing through cities like Timbuktu. Also, Ethiopia is an interesting state to look it as well, having the amazing Solomonid dynasty And basically fighting off lots of invaders and making the most of the relatively desolate land they live in. Again, these states were not necessarily the best in warfare and able to conquer everything in Africa, but each of them had very unique happenings.

I'm not quite sure about Science, but you will find interesting stories of warfare, money, the slave trade, and culture from checking out some of the empires I mentioned ^_^

Specifically look into the he story of Mansa Musa just to see how economically powerful these people were.

Isn't this the Mansa Musa guy that destroyed economies of countries by just visiting them with his immense wealth? Does anyone know any more about him?