No one present in the German capital when the Berlin Wall fell 25 years ago today would ever forget the experience. The uncontrollable cries of joy from family members reunited after decades of enforced separation, the spontaneous hugs between complete strangers; even the most hardened cynic could not fail to be moved.
Nor did anyone doubt the huge strategic significance of the event. For the Wall was more than just fortifications, mines and electrified barbed wires; it was the hated symbol of Europe's divisions, a monument to the Cold War which, over four decades, arbitrarily forced nations around the world to decide whether they belonged to the Soviet-led "East" or the US-led "West". Once that Wall collapsed, everyone instinctively realised that the world had changed: This was raw history in the making.
Yet few analysts - myself included - predicted then how much Europe would be transformed by that experience, or also how deep the divisions between Russia and the rest of Europe would remain. The story of the past quarter-century is one of a huge European achievement as well as a monumental strategic failure, rolled into one.
The tourists who now rush to have themselves photographed next to the few slabs of concrete still standing from the Wall cannot possibly realise what a horrible significance it had for the Germans.
The repulsive sight was not so much the Wall itself, but the dilapidated, boarded-up houses around it which gave the place the ghostly feel of an abandoned movie set, the Achtung Minen - "Attention, Mines" - signs which would suddenly pop up in the middle of a street or a park, and the constant barking of the ferocious dogs kept by East German border guards.
And then, there were the simple wooden crosses scattered everywhere on the Western side, marking the spots where young Germans who tried to flee were mowed down by East German machine guns. The black-and-white photograph which still haunts Germany today is that of Peter Hechter, then aged 18, who, hit by bullets, was left to bleed to death on the barbed wire, with tearful West Berliners on the one side watching in frustrated impotence while East German border guards simply ignored his anguished pleas for help.
My abiding memory is of an elderly East German woman who, on the night the Wall fell, decided to take a stroll into the West. The East German border guards still manning checkpoints asked to see her identity papers. "I'll show you nothing," she shouted at them. "Get out of my way; this is my country, and there is no border here." The guards looked away; she and millions of ordinary Germans like her simply trampled over Europe's dividing lines.
Yet the Wall was crumbling years before it actually fell for, although it kept people in, it could not repel the flow of ideas and technology. East Germany did everything possible to create a separate national identity: its hormone-injected gymnasts routinely scooped medals at the Olympics. However, its people still believed themselves to be part of the wider German nation, indistinguishable from their Western brethren.
The East German regime also tried every propaganda trick to instil pride in the country. But East Germans ignored this altogether by watching West German television instead. As people used to joke at the time, they lived in East Germany during the day, and in West Germany each evening, as they settled before their TV screens.
Although few analysts grasped this 25 years ago, the fall of the Wall was an early indication of two facts which are now commonplace: that no physical barrier is effective in the age of electronic media, and that there is no substitute for good governance.
Weeks after the Wall fell, communism was largely gone from the rest of the European continent. And 18 months after that, the Soviet Union itself collapsed.
The psychological impact was immense, and not always positive. As nations under siege, the East Germans and their other communist East European neighbours developed a unique community spirit. The extended family network was its bedrock, and the smallest achievement was greeted with huge satisfaction. Food was scarce and local goods were shoddy, but the community spirit was strong.