Final answer:
President Kennedy ordered a quarantine zone around Cuba in response to the discovery of ballistic missile sites in Cuba in October 1962.
Step-by-step explanation:
President Kennedy ordered a quarantine zone around Cuba in response to the discovery of ballistic missile sites in Cuba in October 1962. This action was known as the Cuban Missile Crisis and was a key moment during the Cold War between the United States and the Soviet Union. The quarantine zone, also referred to as a naval blockade, aimed to prevent Soviet ships from delivering additional missile materials to Cuba.
Learn more about President Kennedy's response to the Cuban Missile Crisis