Artur Schier, 69, stands on the hillock with his wife, Anneliese. "We think it was here, but we're not sure. In the autumn of my life, I wanted to stand on the spot where the Third Reich breathed its last breath - the Reich that was to last a thousand years."
Eckehart Hagen, a 52-year-old civil servant, has come with his sandwiches. "What terrible suffering came out of this place. It's a place of historical significance."
In reality, Hitler's personal bunker, where the Fhrer spent his final days, is a couple of minutes' walk from the hillock, in the shadow of an east Berlin apartment block.There is no memorial plaque to mark the spot. A more invisible piece of history can scarcely be imagined.
There is a poplar tree, a sandy playground and a small car park - and that's it. Even those who live in the nearby apartments are vague. As one woman says: "Nobody really knows where it is. A memorial? I don't think that's a very good idea." Another neighbour disagrees: "I think we should face up to these things. People want to just wipe everything away."
Nearby Wilhelmstrasse, the street leading south from east Berlin's main avenue, Unter den Linden, was at the heart of the pre-war government district, close to Hitler's chancellery offices, the bunker, and the Brandenburg Gate. Not surprisingly, almost every surviving building in the area has strong connections with the Nazi state that came to an end 50 years ago today.
In some cases, the connection is well known. Hermann Goering's air ministry, one of the few buildings that was still usable after 1945, was soon taken over by the East German Communists as a House of Ministries. A Stalinist- era tiled fresco (which replaced a Nazi frieze) survives, depicting the wondrous co-operation between smiling workers, farmers, engineers and the party. Today, Goering's building has changed hands again: it is used by the German finance ministry, and by the organisation responsible for the privatisation of east Germany in the last few years. A small exhibition in the building's foyer mentions the Goering connection.
Elsewhere, though, the Nazi links are almost hidden. Goebbels's propaganda ministry on Wilhelmstrasse partly survived the destruction of Berlin and today houses the federal environment agency. Nothing hints at the building's past except, perhaps, the original flagpoles, where swastikas once waved.
Just up the road, a new plaque on a dignified old building points out that Konrad Adenauer, the first chancellor of West Germany, worked here before 1933, when he was speaker of the Prussian State Council.
Wandering through the abandoned offices, one breathes in the sweet- rancid smell that filled every East German office in the Communist era. Almost five years after the end of the GDR, this comes as a strange surprise. How can the odour of Communist carpets have survived so long?
Of the building's earlier history, in the Hitler era, no sign remains. New occupants have moved into a few revamped offices in the building, but none of them, tapping away at theircomputers, has any idea what came before.
Everybody knows about Adenauer. After Adenauer, however, the building's occupants were equally noteworthy. This was the headquarters for Hitler's chief lieutenants, Martin Bormann and Rudolf Hess.
Elsewhere, the Nazi legacy has been not so much buried, as discreetly recycled. Thus thedark marble that once covered the walls of Hitler's study was reused by the Communists to give an elegant touch to what is now the Mohrenstrasse underground station in the middle of the old government quarter.
In some cases, the burial of the past has been as much literal as metaphorical. The East Germans bulldozed part of Hitler's bunker complex in 1988, when building some apartments near by. Theoretically, this was for safety reasons. In reality, politics played an equally important part. "They wanted to create a tabula rasa," says Erhard Schreier, an east Berlin illustrator who was asked to make drawings of parts of the bunker at that time.
Since German unity in 1990, the authorities have been almost equally unenthusiastic about digging into the past. Some Nazi frescos, including a mighty German eagle grasping an RAF plane in its talons, were discovered in part of the bunker complex, which had been used by the SS, in 1992. Berlin's architectural advisers wanted the frescos to be preserved. The politicians, worried that neo-Nazis might treat this as a place of pilgrimage, talked of "historically unclean soil". The issue remains unresolved.
Meanwhile, the scenes of the crimes - as opposed to the scenes of the criminals - are clearly marked. Pltzensee prison in north-west Berlin, where many opponents of the Hitler regime were executed, stands as a stark memorial. The bare, white-painted execution room contains five original meat hooks, hanging from a heavy beam. (As a coveted privilege, loyal Nazi officials were allowed to attend the executions.) The former German army headquarters, where Claus von Stauffenberg and others were summarily executed for their part in the plot on Hitler's life, now houses a Museum of the Resistance, documenting what is known as das andere Deutschland, "the other Germany". On the grassy site of the former Gestapo headquarters, an exhibition on the Topography of Terror, first opened in West Berlin eight years ago, is to receive a larger, permanent building - a ceremony today officially marks that decision.
At the site of the former Putlitzstrasse station, from where tens of thousands of Jews were deported to their deaths in Auschwitz and elsewhere, a memorial highlights the "guilt which never ends - and which affects us all". The memorial refers to the neo-Nazis who in 1992 badly damaged an earlier memorial, forcing it to be replaced.
Now, much more conspicuously, and as the result of a public initiative, a huge Holocaust memorial will be built south of the Brandenburg Gate. A large part of the £7m cost of the project will be raised from public donations. As in so many other respects, the trend is obvious: German consciousness of the past is growing, not fading.
As the plans for the Holocaust memorial make clear, the softly-softly attitude towards Hitler's historic sites is not a "don't-talk-about-the- war" form of censorship. Instead, it is a distinctively German kind of self-censorship - fear, in case neo-Nazis might get the wrong idea.
Klaus-Dieter Jurk, who organises tours for curious Germans, insists, however, that the politicians' caution is misplaced. He argues that the SS frescos, for example, should be open to the public: "For the Germans, it's important to address this past. There's no plaque here, to say: 'This was the centre of power. This was where the Second World War began and ended.' It's sad."
Today Berlin is grasping for a new kind of normality. It must put the past away, without locking the drawer and throwing away the key. It is a difficult line to tread - not helped by those who recently launched a dubious initiative called "Against Forgetting", which seeks to trade off Nazi crimes against Germans' own suffering (when millions were expelled from their homes after 1945).
For some radical critics, even the move from Bonn to Berlin is seen as fraught with danger. When Berlin was the capital of Germany, runs the argument, totalitarianism ruled. Why risk a repeat?
Even the former parliament building, the Reichstag - which, in a few years, will again become the German parliament - has been used as a stick to beat Berlin with. The building was abandoned by Hitler, never a great enthusiast of parliaments, after the arson in 1933, which he used as a pretext for granting himself unlimited powers. The clear connection between the burning of the Reichstag and Hitler's absolute power enables some to believe that the building itself is somehow contaminated.
Even now, Germans are divided about what should be remembered or forgotten. Doris Klaus, a brisk 67, stands outside Goebbels's former ministry, and argues: "We grew up with this stuff. But people aren't interested in hearing about it anymore. Anybody who wants to can go to the libraries."
Eckehart Hagen disagrees: "The younger generation should be reminded. Otherwise, it looks as though it has been suppressed. That would be much worse."