I'm not Paul, but I can answer you question.
"I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones."
--Albert Einstein
This famous quote means that World War III will destroy the world with weapons of mass destruction and all that will be left to fight with (if anyone lives through it) for World War IV would be sticks and stones.
I heard this quote in High School (Air Force Junior ROTC) and always though of how true it would probably be.