The world, it seems, has passed this way before. The summer’s events in south Lebanon, Iraq, London, Afghanistan, North Korea and, above all, Iran, have filled the air with a sense of foreboding that few except the very oldest among us have ever felt. We appear to be teetering on the edge of a catastrophe so vast and terrible that only the evocation of similar upheavals in the past is able to do it justice.

Over the last few months pundits and politicians have been competing to be among the first to bring us the bad news in the hope we will hail them as prophets and reward them with our trust. Yet it is only a few years since Francis Fukuyama declared with similar confidence, as Soviet communism finally imploded, taking with it the last skirmishes of the Cold War, that we had reached the End of History. How inadequate his diagnosis reads today as we contemplate the apocalypse.

History provides endless precedents which might help us better understand our feelings of unease. But, if history is truly repeating itself, which episode is most appropriate?

Are we within earshot of the Guns of August that in Barbara Tuchman’s 1962 account of the opening of World War I heralded the slaughter of a generation of callow young men in the mud-filled trenches of the Western Front?

Or are we, perhaps, again witnessing the Gathering Storm evoked by Winston Churchill, who in sonorous tones presented incontrovertible evidence that if left unchecked the ideology of the Nazis would bring our way of life to a bloody end?

Both suggest that Armageddon is upon us. But two other slices of history might serve to illuminate our present plight and suggest ways to avoid losing in “the clash of civilizations,” evident in Iran’s proxy war against the West in south Lebanon and the mullahs’ rush towards nuclear independence.

The first is a period which is little remembered because it was cloaked in wartime secrecy and because its outcome was so quickly overshadowed by unprecedented human disaster: the race to make the first atom bomb.

Attempts to unlock the devastating power of a nuclear doomsday weapon began in earnest from the moment Albert Einstein deduced that splitting the atom would unleash unlimited energy. As World War II clattered towards its conclusion, the German nuclear team was well advanced in rocketry, raining down V1 and V2 (for Vengeance) unmanned bombs on London much as Hezbollah has been showering Israel with arbitrary missiles, and Nazi scientists were making good progress, too, with their experiments in nuclear fission.

But the success of the Allied invasion of Normandy and the Red Army’s helter-skelter advance on Berlin brought not only the swift demise of Hitler but the end of his nuclear program. The recruitment of dozens of Axis scientists — famously personified by Stanley Kubrick’s Dr. Strangelove — into America’s Manhattan Project hastened the perfection of the Allied atom bomb and abruptly cut short the war against Japan.

Iran is currently making rapid progress in its quest for a nuclear weapon, though unlike the Germans and the Allies who had to pioneer a new science, the mullahs’ boffins have been given a flying start by our ally Pakistan in the manufacture of a hydrogen bomb and by the pirate state of North Korea in developing a rocket capable of reaching Paris and London as easily as Tel Aviv. The slow tick tock of U.N. diplomacy is granting Tehran valuable months in which to perfect its murderous technology.

Which leads to the second glimpse of history that can help us better appreciate our current dilemma: Neville Chamberlain’s appeasement of Hitler at Munich. Chamberlain’s mission was well intentioned and honorable, just as those who today advocate engaging President Ahmadinejad in dialogue are well meaning. By negotiating with Hitler, Chamberlain hoped to avoid a resumption of the daily massacres of the Great War.

But Hitler, like Ahmadinejad, was playing for time. And Hitler, like Ahmadinejad, had no intention of abandoning his genocidal mission. He needed to involve his enemies in jaw-jaw to gain a valuable breathing space to bolster his munitions and gather his forces before unleashing war-war upon the rest of Europe.

On Tuesday Secretary-General Annan will follow in Chamberlain’s footsteps as he journeys to Tehran to persuade the mullahs to abandon their nuclear dreams. He will no doubt return bearing a promise that Iran has only peaceable intentions when they, the world’s fourth largest producers of oil, ask for a little more time to perfect their nuclear power program.

Like his predecessors, Mr. Annan is familiar with the lessons history can provide. On his return from Iran, the ever accommodating secretary-general will be careful not to hold aloft a worthless scrap of paper at the airport, nor repeat Chamberlain’s forlorn hope of “peace in our time.”