Twenty-five years after Bertha von Suttner wrote her prophetic essay, Die Barbarisierung der Luft (The Barbarization of the Sky), the scenes of horror and devastation raining down from the sky came true in the small Basque town of Gernika, not far from Bilbao, in northern Spain. The barbarous attacks on an open, peaceful town on 26th April 1937 by bombers from Nazi-Germany caused a furious Picasso to paint his eponymous masterpiece, perhaps the greatest anti-war painting of all time. Earlier...