After World War II the city of Berlin was divided in four sectors. The American, British and French sector were part of the western system while the Soviet (Russian) sector was part of the communist system in the East.

Until the erection of the Berlin Wall on August 13, 1961 Berlin citizen were allowed to cross the border sectors from West to East or East to West Berlin.

West and East city map publishers showed both parts of the city on their maps until 1961.
The after 1976 white painted Wall became also reality on city maps in East Berlin: West Berlin was a white area on city maps published in the East.

East Berliners should not get to know too much information about the other part of their city.

After the fall of the Wall in 1989 November 9 the border between East and West Berlin also disappeared from the city maps.
However the way of the Berlin Wall is still visible indirectly on Berlin city maps. You only have to know that the former border was between the districts of East and West Berlin.