Final answer:
The closest the world has ever come to global nuclear war was during the Cuban Missile Crisis in 1962.
Step-by-step explanation:
The world came closest to global nuclear war during the Cuban Missile Crisis in 1962. This crisis occurred when the United States discovered that the Soviet Union had secretly placed nuclear missiles in Cuba, just 90 miles off the coast of Florida. Both sides were on the brink of war, with nuclear weapons ready to be launched. Fortunately, the crisis was defused through negotiations, and it led to important agreements, such as the installation of a hotline between Washington and Moscow to prevent future crises.