Tourists pass a painting on a segment of the reopened East Side Gallery in Berlin, Germany, Friday. The 105 wall paintings of the former Berlin Wall were restored for the 20th anniversary of the opening of the Berlin Wall in November 2009.(AP)

BERLIN (DPA) – The fall of the Berlin Wall on November 9, 1989 is universally remembered as a night of euphoria and joy in Berlin. But for the city's police forces, it's also remembered as the night they played a key role in reunifying the city, making up new standards and rules on the fly.

Berlin's authorities – in the East and West – started that Thursday with no inkling of what was coming their way over the next 24 hours. But before the night was out, almost all of them had gained impromptu experience in crowd control, ad hoc border crossings and, in some cases, conflict mitigation.

Rainer Bornstein, 54, head of Berlin's 35th police precinct today, was a 34-year-old police superintendent detailed on the night watch for the precinct covering the border crossing at Invalidenstrasse and the part of West Berlin bordering the historic Brandenburg Gate.

Fresh from vacation, Bornstein started his shift going through old paperwork. He was not unaware of the political changes in Eastern Europe, particularly the mass flight of East Germans westward through the now open borders with Hungary and Czechoslovakia. The news had kept him glued to the television during his vacation. ''I've never had a vacation where I watched so much TV,'' he told the German Press Agency dpa.

But that didn't mean he was ready when the news came that an East German Politburo member, Guenter Schabowski, had shocked the world and announced that East Germans had been given the right to travel freely. Nor did he and his colleagues quite know how to handle reports that a border crossing at Bornholmerstrasse was open or that some people had actually climbed atop the Berlin Wall.

Georg Schertz, 74, now retired, but then the head of West Berlin's police, had a similar experience. Not anticipating any major events that night, he was attending a birthday when he heard the news. He rushed to a meeting where West Berlin officials realized they were still unclear what was actually happening.