In this September 30, 1989 file photo, East German refugees look through the fence of the West German embassy in Prague, Czechoslovakia.
In this November 4, 1989 file photo, about one million demonstrators crowd the Alexanderpletz in East Berlin during Germany in a protest rally against censorship and repression. On banners they demanded new leaders and free elections.
In this November 11, 1989 file photo, East German border guards are seen through a gap in the Berlin wall after demonstrators pulled down a segment of the wall at Brandenburg gate, Berlin.
In this early morning, November 10, 1989 file photo, East Berliners get helping hands from West Berliners as they climb the Berlin Wall which has divided the city since the end of World War II, near the Brandenburger Tor (Brandenburg Gate). The citizens facing the West celebrate the opening of the order that was announced by the East German Communist government hours before.
In this October 6, 1989 file photo, Soviet President Mikhail Gorbachev, left, kisses East German leader Erich Honecker after Gorbachev's arrival at East Berlin. At right is Raisa Gorbachev.
In this Sunday November 12, 1989 file photo, West German policeman, left, gives a helping hand to an East German border guard who climbs through a gap of the Berlin Wall when East Germany opened another passage at Potsdamer Platz in Berlin.
This combination of photos shows a father and son, top, riding their bicycles along a section of the Berlin Wall in Berlin on July 1981 and the same location November 3, 2019.
This combination of photos shows people leaving the American sector along the Berlin Wall at allied Checkpoint Charlie, top, on April 1978, in central Berlin and visitors crossing the street at the former allied Checkpoint Charlie on November 5, 2019.
This combination of photos shows the Brandenburg gate, top, behind the Berlin Wall from the Reichstag building on March 8, 1973, and the same location on November 4, 2019.
People line up to see an escape tunnel, underneath the Berlin Wall which divided the city for 28 years during the Cold War, and was make visible for public for the first time, in Berlin, Germany...
...The tunnel was built by a group of people who had escaped earlier from communist East Germany to West Berlin. They wanted to help friends and family to flee to the West, too, but days before it was finished, East German officials discovered and destroyed it.
Memorabilia of East German border soldiers are pictured at the museum of the original escape tunnel from West Berlin to East Berlin at Brunnenstrasse, discovered by former Communist East Germany's Stasi secret police in February 1971, during its presentation to the public in Berlin, Germany.
A map shows the route of the original escape tunnel from West Berlin to East Berlin at Brunnenstrasse, discovered by former Communist East Germany's Stasi secret police in February 1971, during its presentation to the public at a museum in Berlin, Germany.
A man is reflected in a glass protecting a segment of the Berlin Wall at Editorial Perfil in Buenos Aires, Argentina.
Students walk by as people sign a replica wall, during a week-long event commemorating the 30th anniversary of the fall of the Berlin Wall, at Georgetown University, in Washington, U.S.
A general view shows the Berlin Wall memorial at Bernauer Strasse, near the museum of the original escape tunnel from West Berlin to East Berlin at Brunnenstrasse, discovered by former Communist East Germany's Stasi secret police in February 1971, during its presentation to the public in Berlin, Germany.
Statements and phrases are signed on a replica wall, during a week-long event commemorating the 30th anniversary of the fall of the Berlin Wall, at Georgetown University, in Washington, U.S.