What were the two main incidents of the Cold War?

The Cold War lasted over forty years between the Soviet Union and the United States; it is difficult to find only two key incidents between the two nations, as both nations fought proxy wars against each other in Korea, Vietnam, and Afghanistan.
In addition to this, there were also numerous incidents of rhetorical saber rattling. To me, the two key incidents of the Cold War would have to be the first Soviet atomic test and the Cuban Missile Crisis. At the end of World War II, Stalin was annoyed with his American ally because the United States did not share any secrets as to how to build the atomic bomb. The State Department thought that a Russian nuclear test would take place sometime during the 1960s at the earliest; thanks to Soviet espionage and the capture of key German scientists, the Soviet Union dropped their first atomic bomb in 1949. This touched off an arms race between the Soviet Union and the United States which would dominate the political rhetoric of both nations throughout the century.
In the Cuban Missile Crisis, Soviet Premier Khrushchev backed Fidel Castro and stationed nuclear missiles in Cuba that were capable of threatening the US mainland. John F. Kennedy, fresh off his Bay of Pigs disaster, blockaded the island—the potential for World War III was there. Fortunately, the Soviet Union took its missiles out of Cuba in return for the United States removing its missiles from Turkey which were threatening the Soviets. Both sides agreed to more open communication, thus preventing another conflict based on misunderstanding.