February 11, 1945 Yalta Conference concludes Churchill, Roosevelt, and Stalin end the Yalta Conference after negotiating the postwar order in Europe. July 17, 1945 Potsdam Conference opens The wartime allies meet again at Potsdam as tensions over Germany and Eastern Europe sharpen. March 5, 1946 Churchill delivers the Iron Curtain speech Winston Churchill warns that an 'Iron Curtain' has descended across Europe, giving a memorable phrase to the new divide. March 12, 1947 Truman Doctrine is announced President Harry Truman commits the United States to supporting states resisting communist pressure. June 5, 1947 Marshall Plan is proposed The United States unveils a major economic recovery program for Europe that becomes a pillar of containment. June 1948 Berlin Blockade begins The Soviet Union blocks land access to West Berlin, prompting a massive Western airlift. April 4, 1949 NATO is founded Twelve countries sign the North Atlantic Treaty, creating a collective defense alliance. August 29, 1949 Soviet Union tests its first atomic bomb The Soviet nuclear test ends the United States monopoly on atomic weapons. October 1, 1949 People's Republic of China is proclaimed Mao Zedong declares the founding of the People's Republic of China, transforming the global balance of power. June 25, 1950 Korean War begins North Korean forces cross the 38th parallel, turning Korea into the first major hot war of the Cold War. March 5, 1953 Stalin dies Joseph Stalin's death opens a transition in Soviet leadership and policy. May 14, 1955 Warsaw Pact is signed The Soviet Union and its allies formalize a military bloc in Eastern Europe. October 4, 1957 Sputnik 1 is launched The Soviet Union places the first artificial satellite into orbit, intensifying the superpower technological competitio… August 13, 1961 Construction of the Berlin Wall begins East Germany seals the border in Berlin, creating the most visible symbol of the divided Cold War order. October 16, 1962 Cuban Missile Crisis begins The discovery of Soviet missiles in Cuba triggers the most dangerous nuclear confrontation of the Cold War. August 20, 1968 Warsaw Pact forces invade Czechoslovakia The Prague Spring is crushed by a Soviet-led military intervention. May 26, 1972 SALT I is signed The United States and the Soviet Union sign agreements limiting parts of their strategic nuclear arsenals. December 24, 1979 Soviet invasion of Afghanistan begins The Soviet military intervenes in Afghanistan, deepening East-West tensions and provoking a long war. November 9, 1989 Berlin Wall opens East German authorities open border crossings in Berlin, signaling the collapse of communist rule in Eastern Europe. December 26, 1991 Soviet Union is dissolved The USSR formally ceases to exist, ending the Cold War bipolar order.