In the old Prussian Armoury at the end of Unter den Linden is the museum of East German history. To judge by the exhibits, August 13, 1961, was the most glorious day of all. According to the signs, that was when capitalism suffered its greatest ever defeat, when its policy on ``roll back'' ground to a halt. It was the day that the Berlin Wall was built.

Between 1949, when the two German states were founded, and August 1961 about 2,500,000 East Germans had fled to the West. The regime claimed that the wall, intended to seal in its subjects, was an ``anti-fascist'' barrier to prevent Western aggression.

Last month its principal architect, Herr Erich Honecker, was dismissed as party leader. Three weeks later one of his proteges, Herr Gunter Schabowski, has declared it is no longer of any use.

The ugly, straggling boundary mark of communism has come to symbolize the post-war division of Europe. It went up when Herr Willy Brandt, distinguished as an opponent of an earlier Nazi tyranny imposed on the same city, was nearly halfway through his nine years as mayor of West Berlin.

American presidents, notably John Kennedy in his speech of June 1963, have used the wall as a backdrop against which to challenge communism. ``Two thousand years ago,'' he declared, the proudest boast in the world was `civis Romanus sum'. Today, in the world of freedom, the proudest boast is `Ich bin ein Berliner'.''

There were many people in the world who did not really understand ``what is the great issue between the free world and communism. Let them come to Berlin.'' President Kennedy also said, more prophetically, that ``the winds of change are blowing across the Iron Curtain as well as in the rest of the world ... The desire for liberty can never be fully suppressed.''

In 1987 President Reagan used the setting to tell Mr Mikhail Gorbachov: ``If you really want glasnost; if you really want openness; tear down that wall.'' Six months ago in Mainz, West Germany, President Bush called on the Soviet leader to end the division of Europe, starting with the destruction of the Berlin Wall. ``That wall stands as a monument to the failure of communism. It must come down,'' Mr Bush declared.

The wall's graffiti are among the wittiest and most political anywhere in the world. Artists pour petrol on the structure and set fire to it to make it seem to disappear. They daub it with pictures of hope and despair. Perversely it has become the most important tourist attraction in the western part of the city.

But the Wall has also been a killer. A sad memorial near the Tiergarten has a row of crosses remembering those who died while trying to escape over it. Some are marked simply Unbekannt the ``Unknown'' seekers after freedom. A total of 83 are known to have been killed in the attempt and another 125 died trying to get over the heavily defended fence which separates the two Germanys.

Even before the current wave of illegal immigrants, however, more than 200,000 had got out, so the odds must have seemed to make the risks worth taking. In 1964, 57 men, women and children crawled under it in a tunnel. In 1983 two young men fired a line across the Wall with a bow and arrow and were pulled to freedom. Earlier this year a young man flew his wife out in a microlite aircraft he had smuggled in.

For years, border guards watching out for escapes had shoot-to-kill orders, but earlier this year the East Germans announced that the orders had been lifted. People failing to escape across the wall faced up to eight years in jail.

All remaining such detainees are due to be freed by the end of this month.