When you see an opponent civ gunning for culture victory, when is the time to start preparing to anti-cultural war and sack the opponent's capital? Some time ago I found out that when their capital is already legendary and two other cities hit 40 000 (prince/normal), it's way too late and the CV is just mere 10 turns away. In that game, when I realized that I was done for, I amused myself by sending my sorry "SoD" of 28 units on a suicide mission to see what would happen. It was a suicide all right - all of them were massacred immediately upon landing. But it makes me wonder if I could have made it had I just reacted faster. Nukes could have helped of course, but they had been banned by the very same runaway civ, who for that matter also had 5 vassals and strong lead in both tech and military so I would have lost that game one way or the other no matter what (but for some odd reason he never put diplomation to a vote). I just have this tendency to try to ruin my competitors plans whenever I see I'm going to lose, and it would have been fun to deny CV from him.