Which confrontation had the most lasting significance Cuba Nicaragua or Iran?

The Cuban Missile Crisis of 1962 was the most significant confrontation due to its potential for nuclear war between the United States and the Soviet Union. It brought the world to the brink of nuclear conflict and highlighted the dangers of nuclear proliferation. The crisis occurred when the Soviet Union placed nuclear missiles in Cuba, just 90 miles from the United States. President John F. Kennedy responded by imposing a naval blockade on Cuba, bringing the two superpowers to a tense standoff. The crisis was resolved through diplomatic negotiations, with the Soviet Union agreeing to remove its missiles from Cuba in exchange for the United States' pledge not to invade the island. The Cuban Missile Crisis had a profound impact on international relations, leading to the establishment of the Partial Nuclear Test Ban Treaty in 1963 and the improvement of relations between the US and the Soviet Union.