After the U.S invasion in Cuba, the Soviet Union placed nuclear missiles in Cuba for possible future invasions. When the U.S learned about the Soviet's action which threatened the security of the United States, president Kennedy delivered an ultimatum which demanded the Soviet Union to withdraw all missiles from Cuba. After two weeks of possibility that a nuclear war might occur, Khrushchev and the Soviets finally withdrew and the U.S gained victory. The Cuban missile crisis showed the entire world of the dangers of the two superpowers- the United States and the Soviet Union.