Answer: Berlin airlift.
Step-by-step explanation:
In 1948, the Soviet Union blocked all road and rail travel to and from West Berlin, as a response to the refusal of American and British officials to allow Russia more say in the economic future of Germany.
President Harry S. Truman ordered the Berlin airlift, a massive airlift of supplies into West Berlin, until the Soviet Union lifted the blockade in 1949, at a total cost of $224 million and after delivery of 2,323,738 tons of food, fuel, machinery, and other supplies.