What is an event in history that changed mankind's destiny?

312ad The day Emperor Constantine saw the cross floating in the sky.

The discovery that combining copper with a little tin will give you bronze is the most important event. This discovery led the peoples of Europe and Asia down their 4,000-year path toward conquest and world dominance that shaped the world today. The later discovery of iron and subsequent discovery that combining iron with carbon gives you steel, were equally-important events.

Steel technilogically separated the people of Europe and Asia from the people of Africa, Australia, and the Americas. But the path all began with the invention of bronze.

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.