I am reminded of what Momper told me he did in Berlin: With so many things to deal with in those first 24 hours, he nevertheless arranged special bus lanes and shuttles to ferry hundreds of thousands of East Berliners to ooh and aah at KaDeWe, West Berlin’s iconic department store and a temple of consumerism. It was a trip that a young, then-anonymous Angela Merkel also made.

At the time, East Germans expected that “they’d all have a Mercedes or a BMW and be happily prosperous,” says Hope Harrison, the author of After the Berlin Wall. The array of choices had not yet been overtaken by the reality of what was to come, and the accompanying surprise and disappointment that would ensue. Even then, “choosing culture” for East Germans was not the Herculean psychological task it would be for North Koreans. Enough Easterners remembered a world before communism, and some even knew democracy from the Weimar period. North Koreans would need to learn not only how to choose what to buy, but also how to choose whom to lead them. Soberingly, many cannot entirely shed authoritarianism—defectors in the south have expressed dislike for democracy.

With so many factors, planning seems like the only way to mitigate disaster. One person I spoke to questioned the utility of preparedness, though: Momper, West Berlin’s last mayor. No amount of it, he believes, can anticipate what will actually happen.

“I don’t think it’s necessary or even good to makes plans for unification,” he says. “Because what I know about it is this: that it all comes differently from the way we plan it. Even the small parts of unification we had in the process—they were all for nothing.”