At Yalta, Berlin had been divided into four zones (just as Germany had been).
In 1948-9 the Berlin Blockade saw Stalin attempt to 'starve' West Berlin into submission.
Stalin was forced to back down following the Berlin Airlift.
Apart from the Berlin Blockade, those living in Berlin could travel freely- live in the East and work in the West and vice versa.
Khrushchev proclaimed that Berlin was being used by the West as a base for spying and sabotage.
In reality, he wanted to prevent all the highly skilled and…