I'm thinking mainly of African history.
Driving in Tanzania last month, I caught view of mountains that reminded me of the Alps in their sudden steepness, their general outline, and beauty. Of course at the base of the mountains was an entirely different world from the Alps, with palm trees and donkey carts, some paved roads, yes, but still mostly dirt roads, some modern buildings along the main thoroughfares, but thatched roof huts off in the not-very remote areas. Women carrying goods on their heads met my sight, some of them covered from head to toe in the partially Islamic area through which I rode as a passenger in a big Toyota Land Cruiser.
It occurred to me that the main difference in appearance between the mountains I saw and the Alps is that the Alps are covered with castles and the Tanzanian mountains were not…and then in a flash of imagination, I saw everything around me differently.
What if for the purposes of a story, Africa had been settled by medieval Europeans, while Europe had been settled by technologically more advanced Africans? Of course there is a reason Africans come from Africa and Europeans from Europe. But imagine an alternate Earth, in which perhaps through a magical portal like I wrote about in The Crystal Portal, medieval Europeans just happened to arrive in an Africa otherwise empty of humans in an alternate Earth and settled there…while Africans settled in alternate-Earth Europe.
Let’s further imagine that African-settled Europe developed and led the way in scientific advancement and colonial expansion, in parallel with what actually happened in Europe, while European-settled Africa did not advance in technology or in culture. Then the African mountains I saw would be indeed covered with castles. But there would still be donkey carts and dirt roads. There would still be thatched roof huts and women carrying burdens, but they would carry them with their hands or with shoulder yokes instead of on their heads. As medieval women habitually covered their heads (with something called a wimple), the dress code would not be too different from African Islamic…and as some African regions are filled with warlords incessantly fighting one another, so would the castles be filled with unbathed and illiterate knights and lords continually trying to conquer the next castle over...
I didn’t think of all that backstory in a flash—instead I instantly saw in my mind’s eye everyone in my view as European, but still living in “backward” conditions. And I imagined myself being a black man from a land far away with a local white driver, instead of the way it really was, the other way around.
As a story setting, I think such a tale would naturally involve some social commentary. Commentary to the effect that anything negative anyone could say about African culture was in general just as bad or worse in medieval Europe. Which would naturally reinforce the simple observation that humans are all of a common descent, which is something both modern geneticists and believers in the Bible agree on. Our advancements are tied to culture more than anything else and cultures can and do change.
I think for some such a tale might beg the question if there is something about living in Africa that would keep Europeans living there from advancing technologically. Certainly the fact that Europe is divided into many partially-isolated geographical areas (islands, peninsulas, divided by mountain ranges and rivers) tends to separate Europe in to areas suitable for building nation-states--but nation-states that are close enough to one another geographically to be in continual competition with one another. And independent nation-states in close competition certainly contributed to European colonial expansion…and the development of technology in order to outdo other powers.
But for the purposes of a story, I would suggest something simpler should be advanced as the main cause of European technological development: winter.
Winter spurs the development of food storage capacity at the very least. And during winter, the agricultural cycle cannot continue…which leaves time for the study of sciences and technology, for individuals inclined to use their time for that…whereas the African agricultural cycle is “blessed” with the production of food all year 'round, which means there is no winter, no break from farming for peasants, and no break from war for knights and lords. No time for study or science. So if the Middle Ages Europeans had come to Africa a thousand years ago or more, perhaps it's plausible to imagine they would’ve remained medieval up until the day I drove by those mountains…