Iran isn't a likely one due to the fact tat there are already lots of eyes on them. Whatever they have aren't enough to give rise to a world war, local war perhaps but one concerning the whole world, that is another story.
The worrisome ones are actually North Korea and China.
well the only possibility of a WW3 in the future would be a clash between China and the US. over taiwan either that or between Christians and Muslims if hardcore christians take over the US government and decide to call for a crusade against the muslims.
However I rather put the leaders who want world war in a boxing ring and tell them... fight it out yourselves.... dont get the rest of us or your people that dont want war involved.
u think Donald Trump will buy the rights to it? and becomes a reality tv show.... "Vote for the leader you think should recieve a bonus 5 points for good fighting spirit?! Call now to vote! Please note each call is 5 pounds, 10 US dollars, 500 Yuan etc etc etc"