It's been said that the 20th Century was the American Century. World War I saw the collapse of all the great European empires. Even England and France, which were victorious in war, emerged as much weaker nations. America was on the rise. It was challenged by Japan and Germany (again), but those countries were utterly devastated by World War II, leaving America and Russia competing in a Cold War for leadership in a bipoplar world. The collapse of the Soviet Empire at the end of the century left America unchallenged as the only tentpole left in a unipolar world. Americans could be forgiven for thinking that the 21st Century would be the second American Century. But then, as it often does, shit happened.