Nukes are great. Quite a while ago I was playing an Earth map, with a few people initially. However, by the late 1900s, only I and one guy remained. I conquered all of North and South America with Aztec, while he was Persia and possessed a healthy empire in the Middle East and parts of Europe. Problem was that despite my massive lead in cities, he was much better off technologically. This was because he had tons of cottages on all those nice flood plains in M.E. And it became quite obvious he was headed for victory when his spaceship took off. But I was prepared.
I noticed when he completed the Apollo program. So few turns afterwards I sent a small contingent of troops on transports through the southern polar region. It was lying in waiting off the horn of Africa. At the same time I built the Manhattan project, turned all science to 0, and set all 50 of my cities to making ICBMs, using the gold to speed up the process. Turn before he was due to have his victory, I declared war. What followed was 5 minutes of straight nuking. And despite his SDI, I nuked the hell out of every inch of his empire. And of course most importantly of all, his capital. Then my max navigation transports rolled in to raze his cap, which was conveniently on the coast allowing for amphibious assault. This destroyed the spaceship command and control center, causing him to fail spaceship victory.
I'm not sure how he felt about it, because he left the game, but I assume he was not as amused as I was.