Around the world people wonder if this president is strong enough to be a world leader. Russia's leader, Nikita Khrushchev is sure he is not. Angered at American efforts to interfere with Cuba, and determined to prevent another invasion of the island, Khrushchev decides to put nuclear missiles in Cuba and aim them right at America's most important cities and military targets . It will become known as the Cuban Missile Crisis , in which the wrong move could start World War III. Our military leaders urge the President to bomb Cuba . He says no. He will not drop the first bomb. But he is firm with the Russians. He tells them the missiles must be removed . For six long days the world holds its breath. Will there be a nuclear war ? Americans ready nuclear fall-out shelters in case of an attack . Then, all of a sudden Kennedy's unflinching firmness pays off . The Russian ships turn around and take their missiles home . And in the aftermath of the crisis, Kennedy changes his tone and begins to talk about disarmament. He wants both Russia and the United States to stop testing and stockpiling nuclear bombs. He says: "Some say it is useless to speak of world peace. I realize that the pursuit of peace is not as dramatic as the pursuit of war, but we have no more urgent task. We all inhabit this small planet. We all breathe the same air. We all cherish our children's future. And we are all mortal ."

A few weeks after Kennedy makes this speech, and just a year after the Cuban Missile Crisis, Khrushchev accepts the U.S. proposal for a test-ban treaty. "This treaty is particularly for our children and grandchildren," says Kennedy, "and they have no lobby in Washington."