@mekkaokereke @david_megginson one thing about Nigeria remaining unified was the role (my limited understanding) of General Obasanjo who got respect from all sides (afaik preventing Hausa massacre of Igbo, he is Yoruba born).
He was the first (for a long time only) military head of state to hand over rule to a democratic government in the 70s. (Unfortunately the civilian govts were super corrupt and looted Nigeria).
The tribalism is super insidious