The Soviets continued to grab more and more land. Soviet leaders bragged that they would one day triumph over the United States.
    The United States took the Soviet threats seriously. In 1949, the United States,  agreed to form NATO as - and still is - a military alliance . NATO countries agreed that a Soviet attack on any one of them is an attack on all.  If the Soviet Union invaded West Germany, or Norway, or any other NATO nation, all the members of NATO, including he United States, would strike back.  NATO had its own army, to which the United States contributes more than 300,000 troops.
    The United States exploded the first H-bomb in 1952. The Soviets were close behind and exploded theirs in 1953. Now the nuclear arms race was heating up. The United States and the Soviet Union were  building up their stockpiles of fission and fusion bombs. Both also developed better, more efficient ways of getting nuclear weapons to their targets.
     Up to this time, all nuclear weapons had been bombs. They were designed to be dropped from a plane. A ballistic missile is different. It consists of a rocket and a nuclear warhead. The rocket is shot at its target, similar to a gun and it's bullet. A powerful enough rocket can carry a warhead over 3000 miles - across an entire ocean or continent. So the name ICBM, or Inter-Continental Ballistic Missile was given.
    NATO made the Soviets uneasy. Their uneasiness increased in 1954. That year, the United States and and its Western European allies decided to allow West Germany to rebuild its army, navy, and air force. The Soviet Union, which had lost more than 20 million people at the hands of the German armed forces during World War II, was alarmed by the idea of reamed Germany. It responded by setting up the Warsaw Pact. It was an alliance between the Soviet Union and the Communist nations of Eastern Europe.
    The Soviet Union tested an ICBM in August 1957. Two Months later, that success was followed by another - the Soviet launching of the world's first artificial satellite. It was called "Sputnik".