Stalin was worried about the USSR’s safety. In 24 June 1948, he closed all land routes into Berlin. He hoped that this would make the Allies give up their control of Berlin altogether.
The only way to reach the Allied zones of Berlin was by air.
The Berlin Airlift lasted for 11 months. Millions of tons of food, fuel and other supplies were delivered.
Stalin tried to persuade Berliners to register for Soviet supplies in the East – only a small number agreed. In May 1949, after 318 days, Stalin lifted the blockade.
Germany remained divided until 1990. In 1949 the three Western zones became West Germany. In October 1949, the Soviet Zone became East Germany.
Berlin was trapped in Soviet controlled territory and also remained divided.
The 'frontlines' of the Cold War were now drawn in Europe. This led to the formation of military alliances North Atlantic Treaty Organization (NATO) and the Warsaw Pact.