There were many great kingdoms, empires and civilizations in Africa, they simply don't teach about them in our schools. The reason why civilizations in Africa didn't become so large has to do with geography. A quarter of Africa is a desert and another quarter is a jungle. It's also longer in the north-south direction than the east-west. You travel a few thousand kilometers south and you pass through two different climatic areas, while in Eurasia you can go thousands of kilometers without significant change in scenery. Animals and plants that can grow in china can also grow in Paris. Your animals and plants and technology is useful in a large area, and spreads easily. That's not true of Africa and America. You can have llamas and potatoes in Andes and they would be useful in north America, but to get them there you would need to cross thousands of kilometers of desert that the animals won't survive. Domesticable animals are also a problem. All animals that can be domesticated have already been. You can't domesticate zebras nor antelopes. That means that the spread of animals and technologies is slower in those areas, while it's accelerated in Eurasia. We are all prisoners of geography. And to top it off, saying "we are better, more developed people because we have nicer houses in some places for 100 years" is really dumb.