On June 28, 1914, a chauffeur panicked after a failed bomb attack on his boss, took a wrong turn and came to a complete stop in front of a café in Sarajevo where Gavrilo Princip was sitting. Princip, discouraged at the apparent failure of the planned murder, seized the unexpected opportunity and fired the shots that began the First World War, a cataclysm which claimed over nine million lives, ended four empires and set in motion events from the Communist Revolution in Russia to the rise of Nazi Germany. One hundred years later, the world is nervously keeping its eyes peeled for misguided chauffeurs and asking itself whether history could repeat. The great powers are at peace, and trade and cultural ties between nations seem closer than ever before, yet the international scene is in many ways surprisingly brittle. In particular, a rising naval power is challenging an established hegemon, and a "powder keg" region replete with ethnic and religious quarrels looks less stable by the day. In 1914, Germany was the rising power, the U.K. the weary hegemon and the Balkans was the powder keg. In 2014, China is rising, the United States is staggering under the burden of world leadership and the Middle East is the powder keg. Only a few years ago, most western observers believed that the age of geopolitical rivalry and great power war was over. Today, with Russian forces in Ukraine, religious wars exploding across the Middle East, and territorial disputes leading to one crisis after another in the East and South China seas, the outlook is darker. Serious people now ask whether we have moved from a post-war into a pre-war world. Could some incident somewhere in the world spark another global war?