November 9 marks the 25th anniversary of the fall of the Berlin Wall. Over the years, experts have been looking at the reasons for the collapse of this symbol of a repressive regime.

Historians say in the 1960s and 1970s, West Germany developed a strong economy - and West Berlin shared in that wealth.

Berlin Wall Fell Without a Shot Being Fired

Frederick Taylor, an expert on the Berlin Wall and author of the book The Berlin Wall- A World Divided 1961-1989, said East Germany also had a sort of economic upswing, though not on the same level as West Germany.

Berlin Wall Fell Without a Shot Being Fired

"Between 1961 and around 1973-74, the standard of living and the availability of consumer goods inside East Germany improved tremendously," he said. "Washing machines were available, TV sets, even cars - you might have to wait five years for a car, but I think in 1961 three percent of East Germans had a car. By 1975 it was 15 percent. It’s not America, but it’s pretty good compared with what was there before. The problem was that this was all done on subsidized oil and raw materials from Russia."

Berlin Wall Fell Without a Shot Being Fired

In the mid-1970s came the petroleum shock in the Middle East, drastically increasing the price of oil. Subsidies from the Soviet Union were cut, and Taylor says the East German leadership could no longer provide its citizens with consumer goods.

“Imported fruits and vegetables, for instance, started disappearing off the shelves. Just little things - there wasn’t tarmac available for the roads, so the roads got worse and worse. They were pretty bad to start with, but it got a lot worse in the 1970s and moving into the 1980s,” said Taylor. “Buildings were not repaired. Things could not be imported - luxury goods and so on - only available if you had large amounts of foreign currency, hard currency, that is dollars or Deutsch marks or whatever.”

Taylor and others say by the time Ronald Reagan became U.S. president in 1980, the military -- but especially the economic -- vulnerability of East Germany and of the whole Soviet bloc was becoming evident.

Analysts say one man who sensed this vulnerability and who knew the communist system had to change was Mikhail Gorbachev, who became Soviet leader in March 1985.

Serge Schmemann, former Moscow and Bonn correspondent for The New York Times, said “Once Gorbachev introduced this policy of perestroika, of glasnost, once he began loosening the bonds, then all the East European countries began sensing a sort of movement either from within the communist parties or from the bottom up - a loosening.”

In Eastern Europe, the communist parties’ monopoly on power - propped up for decades by the Soviet Union - was on its way to being dismantled. Poland and Hungary led the way.

Analysts say 1989 was a watershed year. Historian Frederick Taylor said one decision by Gorbachev had momentous consequences for Eastern Europe - especially East Germany.

“The really crucial point in 1989 came in the summer when it became clear that Gorbachev, the new reformer leader in the USSR, was not prepared to use the Red Army to suppress dissidents, to suppress protests, to suppress pressure for reform inside East Germany,” he said. “And the moment he, in a sense, pulled away those quarter of a million bayonets that had kept the whole East German communist state in being for 40 odd years, then, then the wall was doomed.”

Gorbachev essentially repudiated the “Brezhnev doctrine” that said if any country tried to break away from Soviet control, Moscow could intervene by force as it did in 1956 in Hungary and in 1968 in Czechoslovakia.

Analysts said once Gorbachev took that decision, events in Eastern Europe and especially in East Germany, accelerated.

Taylor said in August of 1989, the Hungarian government took the momentous decision to open its border with Austria.

“This meant that, in effect, for the first time in nearly 30 years East Germans could get out into a fellow communist country - that is Hungary - and walk into a capitalist country - Austria - and from there go wherever they liked - go to Munich, Miami, Montevideo - wherever they wanted,” said Taylor. “And then those who remained [in East Germany] protested and demanded reform, demanded the ability to travel legally and easily, demanded changes in the government, demanded an end to fraudulent elections, demanded economic improvements.”

The historian said the protests grew throughout East Germany during the months of September and October 1989. They were peaceful. The largest demonstrations were held in the city of Leipzig.