WAR

There is a Harvard Professor called Steven Pinker who has written a book, The Better Angels of our Nature. This work proposes that we are on La Grande Via of the end of wars, especially World Wars.

From Day One of our Ontogeny there was never any evidence that in our nature was an angel. 

The recent doings of the Wall St. Bankers that precipitated the Global Financial Collapse with all its horrendous consequences of human suffering is for us more than sufficient evidence that there simply was not and is not,  in our nature an angel let alone a better angel.

In the cycles of human history there periods of peace. However if you adjudge whether there there are more periods of peace vs more periods of war, you will have the answer that our Steven's proposition is something that is a bit on the wild side. 

As a matter of fact, I have his book in my study and I am waiting for the opportunity to dig into it.

I suggest you get it from a public library vs buying it.