Twentieth Century

In the first half of the twentieth century, Germany, Russia, and Italy were seen as the causes of instability in Europe. What was it about these nations that led to this assessment? Does this view hold true for the period after the Second World War to the end of the Twentieth Century?

and

Some people look at the last one hundred years as a period of great advancement for humankind. Others have referred to it as the "terrible twentieth century." How do you view this issue?