Also, Nagana was a disease endemic to Africa that killed horses, which made it difficult for Europeans to take advantage of African grasslands, and also difficult for them to get inland because their horses would die as they tried to carry stuff. Also, while in the 16th century Europeans did have guns, they were pretty useless, especially without horses, so most fighting was done the old-fashioned way, with swords. That worked pretty well in the Americas, unless you were the Incas or the Aztecs, but it didn't work in Africa, because the Africans also had swords, and spears, and axes. So, as much as they might have wanted to colonize Africa in the 16th, 17th, and 18th centuries, Africa's mosquitoes, microbes, and people were too much for them. So what made the difference? Technology. First, steamships made it possible for Europeans to travel inland, bringing supplies and personnel via Africa's navigable rivers.