European life has changed so much that the situation as it was as recently as 1989, may seem hardly credible to young foreign visitors: a capital city divided into three parts controlled by three foreign powers with the east physically separated from the west.
But there today, still to be seen, are the graffiti-scarred remnants of the Wall, one of the watch-towers and the dingy "death strip" that provided a clear field of fire for the German Democratic Republic guards. The Wall was patrolled by dogs and lined with alarmed barbed wire. Along the east-side there are still some 1950-era tenement flats with windows bricked up.
Large black and white photographs are displayed on placards and hoardings next to the remains of the wall today with text detailing the history. One, dated 1961 and clearly taken in the earliest days, shows a middle aged group fleeing, a woman throwing bags of belongings out of a window and others carrying bags in both hands running for freedom. Another shows an East German soldier, Conrad Schumann, leaping across barbed wire.
Along the wall there are photographs of the faces of the men, women and children who were shot and killed. At least 136 East Germans died as they attempted to escape to the West, the last as recently as 1987.
To mark the 25th anniversary of its fall, lights made of thousands of illuminated, helium-filled balloons - representing a border made of light - will be strung along the former course of the Wall. I was staying with friends in the Prenzlauer district, a short walk from a delightful flea market, that operates on Sundays on Mauerpark, one of the green spaces that emerged on the former "death strip". Nearby is the Spandauer Vorstadt which was Berlin's pre-war Jewish quarter. The area has been regenerated with youthful shops, cafes and bars, populated by young families.
On my second day I took a circular hop-on hop-off bus tour of the major sights, including the Brandenburg Gate, the 18th century arch that marks the centre of the city; the Reichstag, the Neo-classical parliament; Checkpoint Charlie; the Tiergarten, the city's oldest and largest park; and the Kurfurstendamm Avenue which is lined with so many modern international branded luxury stores and boutiques that it makes Oxford Street look positively provincial.
I slipped back into 1950s Berlin the following day by visiting the headquarters of the Stasi, East Germany's notorious State Security Service.
The building has been kept precisely as it was and opened to the public. Sixties' telephones and typewriters stand on desks alongside furniture and filing cabinets that, even in 1989, would have looked cheap and old-fashioned compared with their western equivalents.
The Stasi spied on foreign diplomats, businessmen and journalists via tapped telephones and bugging devices concealed in plant pots, watering cans and various other ingenious places.
They also kept surveillance files on millions of their own citizens to expose and incarcerate so-called "enemies of socialism". To do so, the Stasi had 91,000 full-time staff and 180,000 informers. By comparison, the Nazi Gestapo numbered only 7,000.
Two months after the Wall came down, Berliners forced their way into the Stasi headquarters. Swiftly formed citizens' committees took control of the building and sealed the offices of Erich Mielke, the last Minister of State Security.
Secret police files documented in 100 kilometres of paper files, 1.7 million photos and 28,000 recordings are still in the process of being opened up and analysed. They are being made accessible to the public, revealing in the process not only who was spied upon but who among their friends and acquaintances did the spying.
My next experience of what it had been like to live in the GDR was even more chilling. This was at the Berlin-Hohenschonhausen Memorial Site.
Over the years hundreds of thousands of political prisoners were incarcerated in crowded windowless underground cells, with only a wooden bed and a bucket to serve as a lavatory with a light-bulb shining 24 hours a day.
Together with a dozen or more fellow tourists I stepped briefly into this horrifying hell-hole, where dissidents often remained for years.
The following day I took a break from the Berlin Wall anniversary to visit two of Berlin's most distinguished Jewish memorials. The Holocaust Memorial consists of 2,711 dark grey, oblong concrete forms of varying height. They are laid out in a grid pattern, providing a suitably sombre presence on a prominent sloping site south of the Brandenburg Gate. An underground information centre relates details of the Nazis' planned Final Solution.
More impressive for me, however, was the extensive display of two millennia of German-Jewish history at the Jewish Museum, one of the largest in Europe.
The museum consists of two buildings, one old and one excitingly new. Daniel Libeskind, the Polish-American architect of the new one, which opened in 2001, describes it as being in the twisted, zig-zag shape of a compressed lightning bolt, to represent a deconstructed Star of David.
It has three axes symbolising three paths of Jewish life - continuity in German history, emigration from Germany and the Holocaust.
The tour concludes with an audio installation of Jewish people who grew up in Germany reporting on their childhood and youth after 1945. A new chapter of Jewish life in Germany began with them and continues vigorously today.
Wherever I went I was struck by the extent to which Germany has displayed its past sins and bared its very soul.
At every site some of the men would be wearing kippahs and some of the women would be Moslems wearing headscarfs. At every site too, there would be groups of teenage Germans imbuing the uncomfortable truths of their country and their parents' and grandparents' past.
