Russians are discovered installing offensive nuclear missiles in Cuba when an American U-2 RECON spy plane returns with intelligence photos catching Khrushchev red-handed. Khrushchev categorically denied it until Adlai Stevenson, an American statesman, showed the photos to the United Nations. This angered Khrushchev to the point that he took his shoe off and pounded on the table in an effort to gain attention.
President Kennedy, in a televised address on October 22, 1962, announced the discovery of the installations and proclaimed that any nuclear missile attack from Cuba would be regarded as an attack by the Soviet Union and would be responded to accordingly. He also imposed a naval blockade on Cuba to prevent further Soviet shipments of offensive military weapons from arriving there.
Source: Most of this information comes from recollections of my father. At the time of the Cuban Missile Crisis we were stationed at Dobbins AFB in Marietta, Georgia, near the Third Army Headquarters. He recalls lots of flying time in the C-47 Gooney Bird taking Army VIP's down to Key West, Florida. The Army moved a lot of troops down there during the crisis. Nike missiles were installed in preparation to shoot down any Russian missiles should they appear over the horizon. Most of his work that he did while stationed there is still classified.While Army brats wore dog tags in case the world went up in smoke and we needed some identification, a couple of Navy brats living across the street, twins Kevin and Ken, disappeared overnight. I asked at the bus stop that morning and was told their family were given eight hours notice to bug out.