Nuclear War (scroll down)

The decision to attack Cuba proves to be a costly one. Immediately after the attack on the island, the Soviet Union declares war on the United States, claiming it is defending one of it's vital allies. Soon after, North Korea and China join in as they band together with their communist brethren.

While the U.S. gains allies with France and Great Britain, the war quickly escalates into a world conflict.

No one is really sure who launched the first warhead, but the war proved the theory of Mutually Assured Destruction.

Much of mankind is annihilated in the aftermath.

Some humans managed to survive in caves for some years afterward, but ultimately the destruction and fallout cause the human race to become extinct.