<Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> The Berlin Wall (German: Berliner Mauer) was a guarded concrete barrier that physically and ideologically divided Berlin from 1961 to 1989 . Constructed by the German Democratic Republic (GDR, East Germany), starting on 13 August 1961, the Wall cut off (by land) West Berlin from virtually all of surrounding East Germany and East Berlin until government officials opened it in November 1989 . Its demolition officially began on 13 June 1990 and finished in 1992 . The barrier included guard towers placed along large concrete walls, accompanied by a wide area (later known as the "death strip") that contained anti-vehicle trenches, "fakir beds" and other defenses . The Eastern Bloc portrayed the Wall as protecting its population from fascist elements conspiring to prevent the "will of the people" in building a socialist state in East Germany . In practice, the Wall served to prevent the massive emigration and defection that had marked East Germany and the communist Eastern Bloc during the post-World War II period . </P> <P> GDR authorities officially referred to the Berlin Wall as the Anti-Fascist Protection Rampart (German: Antifaschistischer Schutzwall), by implication equating the NATO countries (and West Germany in particular) with fascists . The West Berlin city government sometimes referred to it as the "Wall of Shame", a term coined by mayor Willy Brandt in reference to the Wall's restriction on freedom of movement . Along with the separate and much longer Inner German border (IGB), which demarcated the border between East and West Germany, it came to symbolize physically the "Iron Curtain" that separated Western Europe and the Eastern Bloc during the Cold War . </P>

When did construction of the berlin wall begin
find me the text answering this question