I hadn't been to Berlin before so I was keen to get to know the city I had read about a little bit (mainly Christopher Isherwood, hardly an up-to-date commentator, I know). I was curious how much the Wall separation still lingered, if at all. And apparently very little is left of that division: real estate prices are now a function of neighbourhood rather than occupation zone.
The main thing I found was the ease of getting around the city on public transport: a really fast, effective and late (24hrs on weekends - and you can take your beer bottle on board!) running S and U Bahn system, plus trams (in East Berlin) and buses - despite a number of mishaps such as a fire in a cabling system, knocking out a crucial part of the Ring line for days.
Five days of exploring a city isn't much in order to get under its skin but superficially experienced I find it an easy-going, laid-back and less stressful than many cities of 4 million people. It's only recently become a spot on the tourist trail and it hasn't got its act together completely yet: the signs are hopeless if you have never been here before and finding your way around is a chore. The BVG (Berlin's public transport authority) needs to get a good map and sign designer in that turns its underground and trams into internationally appealing style icons like the London Underground has been successfully doing for decades. It should certainly start with a better metro map because the current one is way too small to be legible or intuitively useful.
Berlin has had a terrible history in the last 100 years: WW1 aftermath of economic collapse, civil strife, political chaos, hyper-inflation, street fighting, Nazi pogroms and persecutions, WW2 destruction, occupation and division with Wall construction. All of this is still very much part of the fabric of the city: the Wall memorials and preserved fragments, the Topography of Terror exhibit on the former Gestapo HQ grounds, Tempelhof Airport transformed from airlift base to city park, the brushed up Brandenburg Tor and Reichstag, the spanking new Government buildings that even Hitler wouldn't have minded for their modernity and imposing design (although he might disapprove of the faint Bauhaus-style of the Chancellery and Federal Ministries).
But Berliners seem to have a get-up-and-go attitude and just start rebuilding what has been destroyed or take the chance to improve on what has been before. Some truly wonderful museums are a case in point: the Neue Nationalgalerie and the Gemäldegalerie don't only feature world class art but the buildings themselves are worth the visit, even the faithfully reconstructed Altes Museum after decades of wartime destruction, Soviet looting and East German neglect.