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The first human being in space. He is Russian. This trigger the United States to develop techniques for space travel and started the Space Race between the Soviet Union and the United States.
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a US spy plane reported sighting the construction of a Soviet Union's nuclear missile base in Cuba. Since Cuba is very close with the United States, President Kennedy demanded the removal of the missiles. Russians agreed to remove and the United States agreed not to invade Cuba.
https://www.history.com/topics/cold-war/cuban-missile-crisis -
JF Kennedy was assassinated while on a visit to Dallas. Lee Harvey Oswald was arrested for the murder but people think he was not a lone killer. People also believed that there may have been communist of CIA complicity. And of course, the relationship between the United States and the Soviet Union became worse. (It was good after the resolution of the Cuban Missile Crisis.
https://www.jfklibrary.org/JFK/JFK-in-History/November-22-1963-Death-of-the-President.aspx -
Russia, USA, Britain, and France confirmed the rights and responsibilities of countries regard to Berlin.
https://www.nixonfoundation.org/2014/09/berlin-agreement/ -
North Vietnam invaded South Vietnam and captured Saigon. This led the whole Vietnam to become communist. American fear that this will lead whole South Asia to become communist, so they sent troops.