The Mona Lisa is a very thin painting, measuring the thickness of the paint on the canvas, and when you look at it in detail, you will make out no brushmarks. This is because Leonardo da Vinci kept his paint soft, wet and malleable, and then sculpted the form before the paint had time to harden. Fresh oil paint on top of dry paint shows up in a crisp impasto manner, like Rembrandt's works or those of the impressionists.
Dragging the wet paint around and blending the colors together create the soft, smoky qualities he wanted, demanded great skill, because oil paint becomes too dry for blending in a matter of hours, 10 hours at the most. The mouth, for example would then have had to be done in one wet-in-wet session, and then we have to consider the model. A model can not be expected to sit for more than two hours without looking tired.
So my guess is that to paint the lips of the Mona Lisa would have had to be done in less than two hours. To figure out how long the entire painting ... more.
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.