The Berlin Wall was a concrete barrier built by the German Democratic Republic (GDR, East Germany) that completely enclosed the city of West Berlin, separating it from East Germany, including East Berlin. The Wall included guard towers placed along large concrete walls, which circumscribed a wide area (later known as the "death strip") that contained anti-vehicle trenches, "fakir beds" and other defenses.

The separate and much longer Inner German border (the IGB) demarcated the border between East and West Germany. Both borders came to symbolize the Iron Curtain between Western Europe and the Eastern Bloc.

Before the Wall's erection, 3.5 million East Germans had avoided Eastern Bloc emigration restrictions and defected from the GDR, many by crossing over the border from East Berlin into West Berlin. From West Berlin, emigrants could travel to West Germany and other Western European countries. During its existence from 1961 to 1989, the Wall stopped almost all such emigration and separated the GDR from West Berlin for more than a quarter of a century. After its erection, around 5,000 people attempted to escape over the wall, with estimates of the resulting death toll varying between around 100 and 200.

The Berlin Wall was officially referred to as the "Anti-Fascist Protection Wall" (German: Antifaschistischer Schutzwall) by the communist GDR authorities, implying that neighboring West Germany had not been fully de-Nazified. The West Berlin city government sometimes referred to it as the "Wall of Shame" – a term coined by mayor Willy Brandt – while condemning the wall's restriction on freedom of movement.

In 1989, there were a radical series of Eastern Bloc political changes associated with the liberalization of the Bloc's authoritarian systems. After several weeks of local civil unrest following the erosion of political power of the pro-Soviet governments in nearby Poland and Hungary, the East German government announced on November 9, 1989 that all GDR citizens could visit West Germany and West Berlin. Crowds of East Germans crossed and climbed onto the wall, joined by West Germans on the other side in a celebratory atmosphere. Over the next few weeks, a euphoric public and souvenir hunters chipped away parts of the wall; the governments later used industrial equipment to remove most of the rest. The fall of the Berlin Wall paved the way for German reunification. It was formally concluded on October 3, 1990.