Truman Doctrine and Marshall Plan
Also called: European Recovery Program, Containment
The United States declared a policy of containing communism (the Truman Doctrine) and offered massive aid to rebuild Western Europe (the Marshall Plan). The Cold War began in earnest.

E. Spreckmeester (also credited as "I. Spreekmeester"), published Economic Cooperation Administration · Public domain · Source
In 1946 Churchill declared that “an iron curtain has descended” from the Baltic to the Adriatic. On 12 March 1947 President Truman asked Congress for aid to Greece, then fighting communist insurgents, and to Turkey, under Soviet pressure, pledging to support free peoples against communist expansion (containment).
On 5 June Secretary of State Marshall announced the European Recovery Program; from 1948 sixteen Western European countries received some 13 billion dollars over four years. The Soviet Union kept Eastern Europe out and answered with the Cominform (1947) and Comecon (1949). Europe was now split into two camps.