Germans marked the 20th anniversary of their unification in the northern city of Bremen on Sunday. East and West Germany began reunification talks a year after the Berlin Wall tumbled on Nov. 9, 1989 and signed a 45-point treaty on Aug. 31, 1990 authorizing their union, which went into effect five weeks later. German Chancellor Angela Merkel, who hails from the former East Germany, said in a speech that the reason East Germany was able to rebuild itself quickly and win the respect of the international community for the country was because of the unified efforts of both sides.

A survey by German broadcaster ZDF marking the anniversary showed that 84 percent of Germans believe that reunification was the "right decision." Only 14 percent feel it was a bad choice. Over the last 20 years, around 1.4 trillion euros has been spent on rebuilding East Germany, and individuals and businesses spent almost 20 years paying taxes to foot the bill. Still a majority feel reunification was the right choice.

But until the fall of the Berlin Wall, almost nobody projected reunification would happen before the end of the 20th century. Former chancellor Helmut Kohl, who played a pivotal role in German reunification, recalled in his memoirs that even at the start of 1989, nobody foresaw that the Berlin Wall would tumble in October that year. Willy Brandt, Helmut Schmidt and other former chancellors went as far to say that the word "reunification" was unproductive, and leftwing intellectuals criticized any talk of reunification as unrealistic political propaganda.

But the reform-minded Mikhail Gorbachev rose to power in the Soviet Union in 1985, and a wave of democratic movements that began at a shipyard in Poland spread throughout Eastern Europe and eventually triggered a stream of East German refugees to West German embassies in neighboring Hungary and Czechoslovakia, while pro-democracy protests erupted in major East German cities including Leipzig. These events led to a sudden change of history.

Kohl seized the unexpected opportunity for reunification. He pledged massive aid and support for the Soviet Union, which had faced economic collapse, so that Moscow would not resist, while bringing U.S. President George Bush aboard to support the move. That quelled opposition from British Prime Minister Margaret Thatcher and French President François Mitterrand.

The wave of democracy in Eastern Europe was able to spread throughout East Germany despite oppression largely because the West German government allowed 5 million East Germans to visit the West in 1987 alone. It was because of such political and governmental efforts that the sudden and unexpected fall of the Berlin Wall could turn into reunification.

The hurried arrangements for leader Kim Jong-il’s succession in North Korea could be a sign of sudden changes there. But how prepared is South Korea to deal with such events? During the Cold War, East Germany was a key exporter of heavy machinery to other communist-bloc countries, but following reunification the country had to overhaul the entire East German industry. After more than 60 years of isolation from the outside world and more than 15 years of starvation, North Korea would probably need to be rushed to the emergency room.

In the late 1980s, the Soviet Union, which had been the leader of the communist bloc, faced dire economic circumstances, while China, which is North Korea's sponsor, has risen to become the world's second-largest economy. Would China be willing to let a sudden change in North Korea lead to reunification led by South Korea? Or would Beijing use the opportunity to absorb it? It would be a fateful moment for Koreans. The South Korean government and public must realize the looming reality and ensure that it is Koreans who take charge of reunification.