Carthage ... and too many tribes of Gaul to mention.
I believe an attempt at genocide was the extermination of the armenians. (Of which only kim kardashian has survived. Vada-voom) And the stated aim of the roman empire was the extermination of the carthaginian-type people---of whom the jews may be one.
("Cathago delendo est" was their stated motto.) Also the eradication of the germans, or complete degadation, was the intent of the french after WWI ---which had killed a million french soldiers in the french trenches (they didn't even reach germany). Which led to hitler to rescue them. And another "world war" to pacify things.
But the commie enemy screwed that up.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.