After the war, for a long time, overland links between Berlin and West Germany were difficult, not having been the subject of an agreement among the four occupying powers, and this had made it possible for the Soviets to blockade the city. Access by air, on the other hand, had been regulated, with three corridors leaving from Hamburg, Hanover and Frankfurt converging on the civilian and military airports of Tegel (French sector), Tempelhof (American sector) and Gatow (British sector), thereby saving the city from asphyxiation in 1948-1949.

Until the Four Power Agreement of 1971 and the agreement on transit traffic signed by the two Germanies (17^th December 1971), the movements of persons and goods by land or river between East Germany and West Berlin were subjected to all kinds of pettifogging. During the 1970s, overland access to West Berlin was improved, developed and diversified.

West Berlin was then linked to East Germany by rail, and by autobahn to Hamburg, Hanover, Hof and Frankfurt.

4 between West Berlin and East Germany:

- Heiligensee/Stolpe, in the north-west ;
- Staaken, in the west ;
- Dreilinden/Drewitz, in the south-west ;
- Waltersdorfer Chaussee, in the south, reserved for western passengers only heading for the East German airport at Schönefeld.

8 between West Berlin and East Berlin:

- Chausseestrasse, Invalidenstrasse, Oberbaumbrücke, Sonnenallee, reserved for residents of the western sectors ;
- Heinrich-Heine-Strasse, Bornholmer Strasse, for West German citizens ;
- Checkpoint Charlie, for western military, diplomats and foreign visitors ;
- Friedrichstrasse station : in the east, underground stations on lines that passed through both parts of the city were closed and guarded by armed Vopos. Only Friedrichstrasse remained accessible, as it provided an extra crossing point for Germans and foreigners. The border post of Friedrichstrasse exists to this day, having been turned into a concert hall with the suggestive name of Palace of Tears.

Access to the "island"

Crossing points of Berlin