Answer:
During John F. Kennedy's presidency, the United States and the Soviet Union were engaged in a period of intense rivalry known as the Cold War. The two superpowers were constantly trying to outdo each other, both militarily and politically, in a global struggle for power and influence.
One major flashpoint of this rivalry was the Cuban Missile Crisis, which took place in October 1962. The Soviet Union had placed nuclear missiles in Cuba, just 90 miles from the coast of Florida. This posed a direct threat to the security of the United States and Kennedy responded by ordering a naval quarantine of Cuba to prevent the Soviet Union from delivering any more missiles to the island. After a tense standoff that lasted several days, the Soviet Union agreed to remove the missiles in exchange for a US promise not to invade Cuba and to remove US missiles from Turkey.
This crisis was one of the most dangerous moments of the Cold War and came close to starting a nuclear war between the two superpowers. It demonstrated the high level of alert that both the United States and the Soviet Union were operating under during Kennedy's presidency and underscored the importance of finding ways to reduce tensions between the two countries.