The 25th anniversary of the reunification of Germany has been a boon for researchers. All manner of studies have been dusted down or carried out looking at the progress on every imaginable economic and social factor since the poor East merged with the affluent West. There are still differences, some significant, but there is no dispute that it has been a success. It is a lesson for Europe, the Koreas and populations struggling to find common ground.

Germans still hotly debate what has changed. Politics was the least of the reunification worries; it was inevitable that the more populous West's democracy would win out over the East's communism. "Ossis", as those from the East are known, earn only two-thirds as much as "Wessis", more are unemployed, they have fewer industries and not many of their products are on supermarket shelves. Ossis are more likely to be discontent and two million have migrated to the west, leaving an ageing population that is in some areas in decline.

But living standards are now equally high and life expectancies similar. No part of the former Soviet bloc has caught up to the West to the same degree. Older generations see more differences than younger ones. Perhaps in another generation, it will be impossible to tell the two apart.