The Great Rift

Story idea based on the "Guns, Germs and Steel" theory. Apply a few subtle tweaks to the plants and animals of the world and we get a completely different path for civilization.

The cradle of civilization moves from the Tigris/Euphrates valley to The Great Rift valley, centered around Lake Victoria. Ukerewe Island (the largest island) is the capital, with the main city state in the peninsula to the East.

Prickly Pear fruit has been cultivated into a super-food. The sugars and proteins are much higher and fat is a bit higher, it has about 400C per 100g (instead of it's 41C). It already has a high vitamin-C level, but we'll bump that up just a bit. You cannot just drink the juice of a cactus, it's too acidic due to CO2 being stored as an acid (the cactus photosynthesis during the day and breaths at night), our version will go through a phase where the "leaves" die, turn purple and the needles fall off, at this point they basically become water bottles, slightly sweet.

Entada rheedii is edible when cooked with no ill side effects (like hallucinations), maybe play around with the effects of undercooking - could be something to kill fear, or induce mild hallucinations in warriors. It's a vine, so the farms will be more vineyard like. Real version, seeds weigh around 1oz/28g, in our world they'll weigh around 75g.

Foxtail grass may be interesting for it's flammability. Parthenium as a rubber.