"The fall of the Berlin Wall was a logical consequence of developments that were already underway," said author and Oxford University Emeritus Professor Archie Brown. The East German leadership was under pressure to change regulations for people traveling to and from the country.
And when word got out that the gates of the wall were open -- when in fact they were still closed -- tens of thousands of Berliners amassed at the barrier and broke through on Nov. 9, 1989.
"What this showed was that perceptions, even misperceptions, can change reality," he said.
Hear Brown's full interview here:
The massive political changes occurring in Eastern bloc countries -- symbolized by the wall's demise -- took more adjustment in some countries than in others.
The Pew Research Center recently conducted a poll of former Iron Curtain countries as a follow-up to one done in 1991, soon after the fall of the wall, to gauge people's acceptance of emerging multiparty systems and a free market economy.
"We still find broad support in many countries for the change to democracy from a one-party system and the change to capitalism from communism," but approval is less widespread in countries such as in Hungary, Lithuania and Bulgaria, said Pew President Andrew Kohut.
One factor contributing to people's dissatisfaction is their economic situation, he said. "There's a pretty strong correlation with acceptance of the end of communism with how well the economies have performed since and how much better or not better people rate their lives."
In the case of East Germany, where approval is higher, people moved into a country with established democratic institutions, although they seem less positive about reunification today than they did in 1991, he noted.
Kohut describes more of the survey here:
Read the full survey.
Anna Engelke, correspondent for NDR German radio, said most Germans recognize that full reunification will take time.
"It is 20 years, and it sounds long, and it is a generation, but the actual unification will be successful when people don't really differentiate between East German and West German anymore," when talking about their backgrounds or those of others, she said.
Engelke said she has noticed a change in younger Germans, who tend not to make the distinction anymore. "And once we suppress that (differentiation), I think unification is actually completed and we are a united Germany," she said.
Hear Engelke's full interview here:
-- By Larisa Epatko and Stephen Fee, Online NewsHour