In my most recent finished game, the Chinese got Fission and wouldn't trade it with me or any of the other civs. Then came the popup that they were building the UN, so I investigate Beijing and find that it will take them 17 turns to complete.
Since my rep had taken some damage from wars that had interrupted luxury deals, I did what any warmonger worth his salt would do. Declared war on China, signed the rest of the AIs into alliances, and then pounded my way into Beijing which had ended up completing the UN in only a few turns, must have been a GL. Razed the sucker.