Berlin's Mayor Klaus Wowereit illuminated a chain of balloons symbolising the Berlin Wall on Friday.

In a speech to Berliners and tourists, he said Wowereit said the light installation offered "the possibility to tear down the wall for a second time."

"This time people from around the world will send off messages, which are fixed to the balloons, messages for peace and hope that all the walls in the world will fall, concrete walls and the walls in peoples heads," he said.

The 15-kilometre (nine-mile) chain of illuminated balloons along the former path of the Berlin Wall will be released into the air early Sunday evening, around the time on 9 November 1989 when an announcement by a senior communist official set off the chain of events that brought down the Cold War's most potent symbol.

Germany is celebrating the 25th anniversary of the fall of the Berlin Wall, a pivotal moment in the collapse of European communism and the start of the country's emergence as the major power at the heart of a reunited continent.

AP TELEVISION

Berlin - 7 November 2014

1. Berlin Mayor Klaus Wowereit and other officials switching on light installation

2. Various of balloon chain along the river Spree

3. Balloon chain

4. SOUNDBITE (German) Klaus Wowereit, Berlin mayor:

"The 15 kilometre (nine-mile) light balloons go along the former border and symbolise the wall. This is one thing. But they also offer the possibility to tear down the wall for a second time. This time people from around the world will send off messages, which are fixed at the balloons, messages for peace and hope that all the walls in the world will fall, concrete walls and the walls in peoples heads."

5. Balloon chain

6. Public screen showing GDR police officers arresting people who are fighting the regime

7. Man watching documentary

8. Balloon chain

9. People watching video

10. Various balloon chain

11. Balloon chain in front of German Parliament

Thousands of people gathered on Sunday evening in front of Berlin's Brandenburg Gate for an open air event held as part of celebrations marking the 25th anniversary of the night the Berlin Wall fell.

Almost 7,000 balloons were released into the sky, many carrying messages of hope.

The balloons were released from poles that formed a line illuminating a 15 kilometre stretch of the former border between East and West Berlin.

The symbolic act recalled the night of November 9, 1989, when thousands of people from the communist East streamed through gaps in the Berlin Wall to celebrate freedom with their brethren in the West.

"Our family was separated. One part was in the former GDR (German Democratic Republic), even imprisoned," said one spectator, Rose Krueger.

Ana Pereira from Portugal said even the intense cold did not spoil her enjoyment of the spectacle.

"I just texted a friend saying I might have lost some toes and something because it is very cold," she said, adding "It was worth it."

And Berlin citizen Christine Belz said she was asleep when the wall fell 25 years ago, "but today, I wanted to be here."

Among the dignitaries attending was Mayor of Berlin, Klaus Wowereit.

"Nothing and no one may deny the wish for freedom," he said.

"We hope that all the people who are having to suffer from the walls of our times will experience something like we experienced. New courage, upheaval, change to overcome injustice and suffering," he said.

The night was capped with a huge firework display that lit up the night sky over the Brandenburg Gate.

AP TELEVISION

Berlin, Germany - 9 November 2014

++NIGHT SHOTS++

1. Balloons being released at Brandenburg Gate

2. Crowds waiting for release of balloons on poles at Bernauer Strasse that form a line illuminating a 15 kilometre stretch of the Berlin Wall, the former border between East and West Berlin

3. Balloons being released at Bernauer Strasse

4. SOUNDBITE (German) vox pop, Rose Krueger, Berlin resident:

"Our family was separated. One part was in the former GDR (German Democratic Republic), even imprisoned. Now, for the last 25 years, we have a united Germany and this is the greatest joy for us."

5. People taking photos of balloon chain

6. Balloons being released at Bernauer Strasse

7. SOUNDBITE (English) vox pop, Ana Pereira, tourist from Portugal:

"It was very moving, very touching, and I just texted a friend saying I might have lost some toes and something because it is very cold. But it was worth it. It is a moment in time, you know."

8. People taking photos of light installation

9. Balloons being released at Bernauer Strasse

10. SOUNDBITE (German) vox pop, Christine Belz, Berlin resident:

"It was wonderful today. Twenty-five years ago I missed the fall of the wall because I was asleep but today I wanted to be here."

11. Celebrations at Brandenburg gate

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Berlin, Germany - 9 November 2014

++NIGHT SHOTS++

12. Klaus Wowereit, Mayor of Berlin, addressing crowds in front of Brandenburg Gate

13. SOUNDBITE (German) Klaus Wowereit, Mayor of Berlin:

"Nothing and no one may deny the wish for freedom and self-determination, nowhere. And nothing will protect authoritarian regimes from the call for democracy and justice in the long run. So we hope that all the people who are having to suffer from the walls of our times will experience something like we experienced. New courage, upheaval, change to overcome injustice and suffering. This is the message which we are sending together today from the Brandenburg Gate in Berlin."

14. Various of firework display at Brandenburg Gate