The document summarizes the Berlin Blockade and Airlift that occurred in 1948. It describes how the Soviets cut off access by road and rail to West Berlin in response to the western allies introducing a new currency. In response, the US initiated an massive airlift to supply West Berlin by plane. Over 15 months, planes delivered necessities to the city's 2.5 million residents every 2 minutes. This airlift showed Soviet attempts to isolate West Berlin would not work, and they eventually backed down and lifted the blockade. The blockade and airlift demonstrated the need for a unified western military alliance, leading to the formation of NATO in 1949.