Earlier, Chancellor Angela Merkel said the fall of the wall had shown the world that dreams could come true.
Tens of thousands of people attended events, including a "citizen's party" at the Brandenburg Gate.
The Berlin Wall was built in 1961 to stop people fleeing the communist East.
Its fall in 1989 became a powerful symbol of the end of the Cold War.
The white balloons - perched on 3.6m poles to match the height of the wall and stretching for 15km (nine miles) - were released one by one to symbolise its disappearance.
The Berlin State Orchestra under Daniel Barenboim played Beethoven's Ode to Joy.
The release came amid a massive open-air party at the Brandenburg Gate. Earlier at the party, UK performer Peter Gabriel sang a version of David Bowie's Heroes. (+ videos) » | Sunday, November 09, 2014
