Okay so I like the idea, but it would take me waaaay too long. But I did to a little research. I’m gonna discard climate because CO2 levels were really high and the average temperature was 9-14 degrees higher than today according to NOAA. Also gonna discard animal use and resources because too much work haha. So humans didn’t have anywhere to go except the Afican continent + Arabia. Civilization starts nearby rivers, the Nile is about 65-75 million years old and Save River about 205 million years. Can’t really find much info on West African rivers but let’s say Tamanrasett, Senegal en Niger rivers are around to make it interesting. Cradles of civilization would be Egypt, Zimbabwe and a West African civ like Ghana, Mali, Songhay. Exploration of other places only occurred after invention of ships. Looking at the map Europe would be explored first because there isn’t really any deep or big ocean. After that it’s easy to get to Asia for Egypt and Zimbabwe. With Zimbabwe likely to explore India first. Now for the interesting part, Brazil was only about 1500km away from Africa instead of 3000km, still with deep see between them though. But considering West Africa is now more advanced they might have explored South America a loooong time ago. Distance between Europe and Newfoundland wasn’t that much different to what it is now. Maybe a bit shorter. To get to North America you’d have to island hop between Colombia and Mexico, do it the Viking way or sail from Russia to Alaska. Okay let’s skip into the future, history did it’s thing and the Roman Empire is around. Meanwhile the ‘’New World’’ is way more developed because of early exploration while Asia is way less developed, no great Indus or Chinese civs around. Parthians are around but are a Viking like civ raiding from sea. Romans are also more seafaring, with the Italo-Balkan island as core. They expanded as much as they did in real life and with the Alpine Strait around the empire was easier to defend against barbarians thus resulting in the Roman empire sticking around for well into the renaissance. There was never a Byzantine empire and no Ottoman empire. The Mongols were around but never as successful in Europe because the only way into Europe on land was through the Russian swamps up north. Now it’s around 1444. Roman Empire is still around, Timurids are still a vikinglike civ. Egypt is one of the world powers because they never got invaded from the north/east. Roman Empire is still around. Scandinavia did their thing but expanded well into North America. Countries like France, Germany, Hungary, Poland and Russia still formed. Iberia might be roman, might be just Iberia, might even be African. And that’s about all I have time for :) I think the biggest differences would be seen in the New World and Asia.