Concerts and exhibitions are being staged in the city and Chancellor Angela Merkel will later attend a huge open-air party at the Brandenburg Gate.
White balloons marking a stretch of the Berlin Wall will be released to symbolize its disappearance.
The Berlin Wall was built in 1961 to stop people fleeing from Communist East Germany to the West.
Its fall in 1989 became a powerful symbol of the end of the Cold War.
Angela Merkel will be joined for the festivities by former Polish trade union leader Lech Walesa and Mikhail Gorbachev, the last Soviet leader.
The wall stretched for 96 miles through Berlin but today only about 2 miles of it still stands.
Within a year of its collapse, Germany – divided after its defeat in World War Two – was reunited.
More than a million visitors have descended on Berlin for the weekend of festivities that will culminate at the Brandenburg Gate.
The monument itself was inaccessible during the partition of Germany and is seen as a symbol of the country’s reunification.
On November 8, people posed for photos in front of the few remaining graffiti-daubed slabs of the wall, or read information boards about life under Berlin’s 28-year division.
Others admired the art installation of almost 7,000 white balloons, pegged to the ground and winding along a 9 miles stretch of the wall’s route.
At the bustling Potsdamer Platz, which was once cut in two by the wall, a small crowd watched archive footage of East German demonstrators chanting: “We are the people.”
2ml5rTgoVU8Image source: Wikimedia Commons President-elect Donald Trump celebrated his election victory at the Ultimate Fighting…
Millions of voters across the US chose to return Donald Trump to the White House…
Donald Trump declares victory in the US election as he addresses jubilant supporters in Florida.…
Stocks around the world are rising as Donald Trump appears to be on the cusp…
Donald Trump has won Pennsylvania, North Carolina and Georgia and taken a lead over Kamala…
Quincy Jones, the celebrated musician and producer who worked with Michael Jackson, Frank Sinatra, Ray…