Chancellor Angela Merkel leads commemorations for those killed trying to flee communist East Germany, ahead of a giant festival to celebrate the peaceful revolution that ended Europe's Cold War division on November 9, 1989.
Merkel, 60, who grew up under the repressive eastern regime, said in her weekly podcast yesterday that the reunified capital of Berlin had become "almost a symbol of Europe's unification after the Cold War". "This city has written history," she said later at an event held at Berlin's modern art museum, the Neue Nationalgalerie.
"The human urge for freedom cannot be subdued in the long run."
A highlight is expected to be the symbolic release of nearly 7,000 illuminated white balloons, pegged along a 15-km stretch of the Wall's former 155-km path, around 1820 GMT.
The glowing orbs will begin floating into the night sky from the iconic Brandenburg Gate, the symbol of German unity, to the stirring strains of Beethoven's "Ode to Joy", the anthem of the European Union.
It is due to be watched by Merkel, the last Soviet leader, Mikhail Gorbachev, 83, former Polish president and freedom icon Lech Walesa, 71, as well as German head of state Joachim Gauck, 74, a former pastor and rights activist in the East, and Hungarian ex-premier Miklos Nemeth, 66.
Gorbachev warned yesterday that the world was on the "brink of a new Cold War", amid tensions between the West and Russia over Ukraine. He complained of a "breakdown of trust" in recent months, adding: "Let us remember that there can be no security in Europe without German-Russian partnership."
Unlike events for the 20th anniversary, no visiting heads of state or government are due, with the organisation this time more grassroots.
Entertainment will range from the Berlin State Orchestra under the baton of Daniel Barenboim to a fireworks display and performances by East German rock band Silly and techno musician Paul Kalkbrenner.
British singer-songwriter Peter Gabriel will perform the Wall anthem "Heroes", which David Bowie recorded when he lived in then West Berlin.
Also on stage will be veteran German rock singer Udo Lindenberg, whose 1983 hit "Sonderzug nach Pankow" (Special train to Pankow) mocked East German leader Erich Honecker for denying him permission to perform.