Red stars are removed as communism relinquishes its grip in central Europe
The year 1989 reshaped the world. Its news stories - from Tiananmen Square to the fall of the Berlin Wall - are now historical marker posts. BBC Diplomatic Editor Brian Hanrahan watched many of the events at first hand, and will retrace his steps this year.
One of the paradoxes of 1989 was that communism was destroyed by its own system. I'm not thinking here of the weight of economic collapse, which hollowed out the whole Soviet Bloc.
Painful though it would have been, the countries of Eastern Europe and their Soviet overlord could have limped on for many years - their people suffering and their influence declining. They would have been marginalised but left alone until they eventually collapsed, probably with much bloodshed.
John Simpson's 1989 report on the visit to the UK of Mikhail Gorbachev
What short-circuited this process was the Stalinist power structure of the Soviet Union. The system allowed the general secretary of the Communist Party to acquire almost total control of the party and the country.
By 1989 Mikhail Gorbachev had consolidated his power base and was able to drive through his own policies regardless of the opposition among his colleagues.
What marked him out from previous leaders and makes him one of my political heroes, is that he abided by a basic principle that politics should not be based on coercion.
And although he neither liked, nor expected, nor wanted the consequences, he stuck to his principles. When the wrong results came in, he let the chips fall where they lay, and the Soviet Empire and the Soviet Union fell with them.
Mr Gorbachev had been steadily setting out his philosophy. He told a Communist Party conference in 1988 "the imposition of a social system, a way of life, or policies from outside by any means, let alone military force, are dangerous trappings of the past".
In December at the United Nations he renounced the use of force in international affairs. His more hard-line colleagues recognised this as suicidal for the Communist Party and its leadership, but they could not stop it. They were shut out by their own system.
I arrive in Moscow and at the airport I am told that troops have marched into Tbilisi... Was this truly necessary?
By the time Mr Gorbachev visited London in April 1989, the shine was coming off his leadership. In Moscow's streets, people were grumbling that for all his fine talk, life wasn't getting better.
More dangerously, those who ran the Soviet army and security services were growing unhappy with his leadership.
It was already obvious that the enthusiasm with which he was greeted abroad was not matched at home. While he was absent there were nationalist demonstrations in Georgia and, in a throwback to the past, the old guard leadership sent in troops to suppress them.
They hadn't opened fire but had beaten 20 Georgians to death with entrenching shovels. Mr Gorbachev was appalled. It was against everything he stood for. Secret minutes from the politburo show him raging against those responsible.
"I arrive in Moscow and at the airport I am told that troops have marched into Tbilisi. Of course I did not comment publicly. But what is going on here? Was this truly necessary? Was the curfew truly necessary? Of course not. We should have gone directly to the people and talked to them."
Without Gorbachev, communism's death throes would have been long, and far more dangerous
Around Eastern Europe there was a similar division of opinions about Mr Gorbachev's new thinking. Most of the leaders were communist fossils buried in a system that repressed change. But General Jaruzelski who ran Poland saw a chance to end the long-running dispute with Solidarity.
The trade union movement had been outlawed for most of the decade but, inspired by the Polish Pope and supported by the West, it had slowly debilitated the Polish economy and government.
Poland's communists opened negotiations with Solidarity's leaders - the famous round table which ran from February to April . On 17 April they signed a deal to hold elections and allow solidarity to take part.
This was the breakthrough - it rolled back the 40 years of authoritarian rule. The communists were starting to think the unthinkable. General Jaruzelski flew to Moscow to get approval for the possibility of power-sharing with Solidarity.
It was complicated deal - and the Polish communists thought they had secured safeguards that would guarantee them a majority. Instead, when the elections were held in June, Solidarity swept the board.
Brian Hanrahan reports from Belgrade during unrest over Kosovo in 1989
The communists couldn't even get enough votes to capture the seats reserved for them. So complete was their moral defeat that two small puppet parties who had always backed the communists now bolted to Solidarity.
Poland found itself with an elected non-communist government. With the Polish precedent to follow, challengers to communism started to pop up all over the Soviet Bloc. The collapse of communism had started and the other leaders could see it.
East Germany and Romania privately canvassed the idea of a Warsaw Pact intervention of the kind which had crushed Czechoslovakia in 1968. But with Gorbachev in charge, their plans gained no traction.
Thinking back, it's astonishing that one man - though facing stern internal opposition - could give history such a decisive push. Without him, communism's death throes would have been long, and far more dangerous.
And it worked the other way too. In March 1989 I found myself standing on a country road in Kosovo, watching Yugoslav tanks advancing on Pristina.
I didn't know it then but it was the first military move in the long drawn-out agony of Yugoslavia. Slobodan Milosevic, the Serb leader, was exerting his influence to block the break-up of Yugoslavia.
Imagine the horror if there had been a Soviet leader who had behaved the same way. Europe has a lot to thank Mikhail Gorbachev for - and he is still a lot more popular abroad than at home.
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