A century ago, a German foreign minister, standing in the British Foreign Office having just signed a pact that sought to guarantee peace between the nations of Europe and avoid a descent into another world war, said the words: “We are bound to one another by a single fate. If we go down, we go down together; if we are to reach the heights, we do so not by conflict but by common effort.” For Gustav Stresemann and the other foreign ministers who signed the Locarno Treaties, that moment of hope was short-lived: a decade and a half later, worldwide conflict erupted once more.