The Berlin border crossings were created as a result of the postwar division of Germany. Prior to the construction of the Berlin Wall in 1961, travel between the Eastern and Western sectors of Berlin was totally uncontrolled, although restrictions were increasingly introduced by the Soviet and East German authorities at major crossings between the sectors. This free access, especially after the closure of the Inner German border, allowed the Eastern Bloc emigration and defection to occur which resulted in the erection of the Berlin Wall.