After the United States tried to invade Cuba and failed (Bay of Pigs), the Soviet Union attempted to supply Cuba with nuclear missiles. These missiles in Cuba would have allowed the Soviet Union to effectively target almost the entire United States. In response the United States sent a large number of ships to blockade Cuba thus preventing the Soviet Union from delivering these weapons. The United States and Soviet Union came to agreement that the Soviet Union would no longer give nuclear weapons to Cuba as long as the United States does not invade Cuba again. This was the highest period of tension during the Cold War and it was the closest the world came to a nuclear war, with possible global conflict to follow.