
die Grenzöffnung
border opening
The act of opening a previously closed national border and allowing free movement of people. In Germany, the term is very strongly associated with the fall of the Berlin Wall and the opening of the inner-German border in 1989.
Die friedliche Revolution in der DDR führte schließlich zur Grenzöffnung am 9. November 1989.
The peaceful revolution in the GDR eventually led to the border opening on November 9, 1989.