"A century ago this month, Europeans stood on the brink of a war so devastating that it forced historians to create a new category: 'World War.' None of the leaders at the time could imagine the wasteland they would inhabit four years later. By 1918, each had lost what he cherished most: the kaiser dismissed, the Austro-Hungarian Empire dissolved, the tsar overthrown by the Bolsheviks, France bled for a generation, and England shorn of the flower of its youth and treasure. A millennium in which European leaders had been masters of the globe came to a crashing halt."
With lessons learned from WWI, Graham Allison asks, how likely is another world war?