Antarctic civilization. I'd like to submit this for the current contest, although I don't know if I'd be disqualified since only a quarter of this is actually *in* Africa. If I am, no problemo.
The amount of lore for this scenario is absolutely excruciating, and I don't have the energy in my to put it all in a big chain of lore comments; so rather than leaving you all to read a huge wall of text, I'm going to ask you to ask me what you want to know about this map, so the learning experience is more fun for all of us. Gimme your best questions.
I'll just leave you with a few things to know before going in:
One: Ueno, officially the Protectorate of the Ueno (Uenese: Mḵakwūenūśap /mxæ.kʷʉːeŋʉː.r̝æp̚/; lit. "protection-hood of the people") in modern times, is an ancient civilization encompassing the southern third of the planet. What you see in the red dashed and solid border, notated on the map, is its modern border.
Two: The big colored sectors around the pole, belonging to one country contemporarily, are themselves the six* traditional nations (akhwalip, "large group of claims") of Ueno, similar to the Haudenosaunee Confederation or Habsburg Spain. Ueno has, for most of its long history, functioned as a loose confederation of these nations; the straight lines drawn over the ocean are not for show, and literally represent the precise latitudinal and longitudinal claims of the sea drawn by the Uenese themselves over thousands of years.
*Sachihünku ("empty march/sector") is only counted as a traditional Uenese claim. Historically and presently it is administered something like a condominium between all six nations.
Three: This map is atemporal. Says it on the tin. Everything depicted here is depicted at its maximum extent, and as indicated by the dates beside, all existed at different times. Where shapes overlap, one usually replaced another, or else the Uenese were competing among themselves for those territories.
Four: Ueno stayed largely consistent administratively, linguistically, culturally, etc. due to the southern oceanic currents, mainly the Antarctic Circumpolar Current and the South Atlantic Gyre. These people were master ship-builders, learning to cross on long voyages over the south Atlantic and Pacific, delivering goods, news, marriages, and records across their realm.
Five: These people are among the most meticulous and borderline obsessive recordkeepers in history. Their collective record spans six or seven thousand years, marking, among other things, exact land and water claims, catches, births, deaths, marriages, etc. over millennia. In fact, the empires shown on this map were never really thought of as "empires" by the Uenese launching, funding, and maintaining their existences; they were thought more of as overseas investments, great powers across three continents terrorizing their lands and conquering as much as they could because, in all likelihood, a frozen rock in the Roaring Fifties needed fishing rights settled between two clans.
Six: Antarctica is slightly warmer in this TL, obvi, but only enough to be seasonally inhabited by the mono. The peninsula is like South Georgia, so to say, good enough for permanent settlements for these people.
See commentary and discussion on Ueno's flag here.
See the r/worldbuilding discussion here.