At a solemn ceremony in a church standing on the former “death strip” that divided East and West, Merkel said the Berlin Wall reminds “us that we have to do our part for freedom and democracy”.
“The values upon which Europe is founded … they are anything but self-evident. And they must always be lived out and defended anew,” she told guests from across the continent.
On November 9, 1989, East German border guards, overwhelmed by large crowds, threw open the gates to West Berlin, allowing free passage for the first time since the Berlin Wall was built.
The momentous event would end up bringing the communist regime crashing down, and led to German reunification a year later.
But the euphoria for liberal democracy that characterised the epochal event then has somewhat dissipated three decades on, as the Western alliance that helped secure those achievements is riddled with divisions.
Cracks have appeared within the European Union as former eastern bloc countries like Hungary or Poland are accused by Brussels of challenging the rule of law.
Domestically, Germany is also struggling with a resurgent far right, which has gained a strong foothold in its former communist states by championing a nationalist and anti-immigration message.
Merkel said the past must serve as a lesson, noting that the collapse of the Berlin Wall is “history and teaches us that no wall that keeps people out and limits freedom is so high or so wide that it cannot be broken through”.
“That applies to us all in East and West: we stand stripped of any excuses and are required to do our part for freedom and democracy.”
Under grey skies, President Frank-Walter Steinmeier and his counterparts from Poland, Hungary, Czech Republic and Slovakia put roses through cracks in part of the Wall that still stands at Bernauer Strasse, in the north of central Berlin.
Steinmeier underlined the role played by central Europeans in bringing about the peaceful revolution that demolished the communist regime.
But later at lunch, the president also noted the graver atmosphere at this juncture compared with other celebrations marking the key event in the German calendar five or 10 years back.
“In Germany, we are debating and yes, fighting, more than before, about German reunification and its consequences,” he told his central European guests.
“In Europe too, in your countries and also between the European societies, there is a more intensive and fiercer struggle not only on the future of Europe but also on the interpretation of the past.”
And differences are not only resurfacing between the former east or west blocs.
Two days before the anniversary of the epochal change, France’s President Emmanuel Macron made an explosive charge that transatlantic partnership NATO was suffering from “brain death” and that Europe itself was “on the brink”.
Merkel responded with uncharacteristic sharpness, saying on Thursday: “I don’t think that such sweeping judgements are necessary.”