On May 12th 1949, the Soviet Union ended its blockade of West Berlin. Instigated on the 24th June the previous year, the blockade prevented all rail, road, and water transport between Berlin and the West of the Germany.
Germany had been divided into four parts at the end of World War 2 with Britain, France, the USA and the USSR each administering one area. Buried deep in the Soviet zone, the Berlin was also divided into four sectors. It was to the area controlled by the Western powers that the USSR blocked access.
Faced with the possibility of all-out war if they forced their way through the blockade, the Americans opted to make use of the three air corridors that provided unrestricted aerial access to Berlin. The USSR knew it risked war if it shot down any aircraft, and was therefore powerless to stop them. Launched four days after the blockade, the Berlin Airlift went on to see over 200,000 individual flights transport up to 8,500 tons of supplies each day.
The pilots and ground crews soon settled into an efficient rhythm. An unusually short winter also helped to keep the airlift running. By the spring of 1949 it was clear that the Western powers had achieved the impossible by supplying West Berlin by air alone. On the 15th April the USSR expressed a willingness to end the blockade and, after a period of negotiation, it was lifted at one minute past midnight on 12 May 1949. The blockade was over, but the Cold War had just begun.