Less than six years later, in May of 1945, Hitler was dead, Germany prostrate and being divided by its occupiers and the world had been remade.
And 66 years later, we can see just how thorough that remaking was to be. The uneasy peace of 1945 morphed soon into a Cold War that defined the next 45 years. In the process, the great colonial empires of Britain and France and Russia disappeared, a mass middle class was born and unparalleled prosperity made economic growth seem part of the natural order.
It blossomed first in the United States and then in Western Europe, followed by Japan, the Asian Tigers and Brazil and now China and India are energetically following. The defeated powers of World War II, Germany and Japan, became sleekly prosperous pillars of the new international system that the United States has forged with its victory.
Over the past two decades, we have seen the greatest transfer of wealth in the history of humanity, far beyond the most generous dreams of the international development theorists, as the rich world of Group of Seven countries began importing ever more from the emerging markets, enriching them in the process.
The lesson here is that great historical events take time to unfold; the nature of the peace to be secured by great victories is seldom immediately apparent.
Ten years after Hitler's defeat the imperial retreat and the mass prosperity had yet to happen. The impact of some of the key technologies to emerge from that war, jet travel and television, nuclear power and computing, was just beginning to be felt.
So 10 years after 9/11, with Osama bin Laden dead and al-Qaida splintered and fractured, it may be soon to interpret the real impact.
There is no shortage of glib analysis, suggesting that 9/11 signaled the end of the American era as a vengeful presidency launched two costly, debilitating and inconclusive wars in Iraq and Afghanistan. Last week, Brown University's Watson Institute for International Studies estimated the total cost at $3.7 trillion, including veterans' future healthcare, with a combined global death toll of around 250,000 people.
But before swallowing simplistic theories about the decline of the West, recall that phrase that was current two decades ago, the one that said "the Cold War is over and Japan won." It doesn't seem like that in Japan today and those who suggest that the new era of China's dominance is at hand still have an uphill argument to make.
Perhaps the thought-provoking single difference between the world of 9/11 in 2001 and what we see today has taken place in the Islamic world. Taliban, Saddam Hussein, Moammar Gadhafi and Hosni Mubarak have all been toppled. Morocco and Jordan seem to be remaking themselves as constitutional monarchies with real parliaments.
Only a fool would dare to predict the future course of the Arab Spring. But only a greater fool would deny that something fundamental has shifted in the region and that a crucial factor in that shift was the controversial decision of George Bush and Tony Blair to invade Iraq in 2003.
That war, wretchedly misconceived in so many of its aspects, signaled two important developments. The first was that the West was no longer playing crude realpolitik, prepared to tolerate vicious dictators if they played a useful strategic role, whether in supplying oil or balancing the power of Iran. The second was that at least in its rhetoric the West was serious about promoting democratic reforms and responsible government in the region.
It now seems that, even if French and German politicians didn't believe this, many ordinary Arabs did and a great number of Persians were to risk life and liberty in pursuing those ideals in the teeth of viciously repressive regime.
This isn't to argue that the war has been a great success. Iraq remains a febrile and unstable entity. Afghanistan looks poised to return to its traditional tribal ways after a Western withdrawal in the next few years. Pakistan has been driven to the brink of failed-state status.
But it is no longer possible to exclude the prospect that Iraq may become by the end of this decade a moderately prosperous, moderately democratic beacon for Arab progress. There may even be respectful statues to Bush and Blair in Baghdad and perhaps to French President Nicolas Sarkozy in the Libyan capital of Tripoli.
Of course, future historians may look back and say the real impact of the wars on terrorism was the extraordinary boost that it gave to robotics, with the U.S. Air Force now training more pilots to fly drones from remote locations than to sit in cockpits. They will probably say that the dramatic decline of Islamic birthrates that gathered force in the last decade was of greater social impact than the wars. Future historians are likely to have unpredictable and even strange ways of assessing our present when it becomes their past.
But just as anyone judging the results of World War II from the mid-1950s would probably have got it extraordinarily wrong, we should beware now of facile assessments of 9/11 except to note that, given half a chance, the Arab people appear to prefer liberty to terrorism and many have risked and even given their lives to offer their countries the chance to try it.