Map of the Berlin Wall, showing checkpoints. Key:
Solid line: the Berlin Wall;
Dotted line: edges of East Berlin;
Blue dots: Checkpoints open to Germans only;
Red dots: Checkpoints open to Germans and non-Germans
Own work, based on File:Occupied Berlin.svg by User:Stefan-Xp, derived from File:Berlin-wall-map.png by User:ChrisO.
Ericmetro