The Omega
Completely Insane
I think that if a largescale nuclear war breaks out, with countries hurling nukes at each other, it would eventual result in the destruction of mankind, where you appear with only a few settlers and military units. all cities that were not destroyed in the nuclear war could be retaken, but nuclear radiation woud severly limit the old cities growth. Also, most tiles would be changed to tundra, desert, or raidioactive wasteland, limiting the growth of civilizations. I think this would make less people use nukes, since the us and soviet union didn't avoid nuclear war just because people wouldn't like them if they did it.