It was an American Cannon in my current Civilization IV Beyond the Sword file, about 100 turns ago and this was on Sunday. I'm modernizing my forces now that I have no techs left in preparation for another war with America, since I have about 160 units left to upgrade out of my total forces of around 400 units (at least, I think it's just 400 total. I keep building more modern armor because stacks of doom are pretty essential in a conquest victory, so that number may actually be considerably higher). This time, it shall be Tokugawa's turn to rule the world! Provided Lincoln doesn't possess more than 10 tactical nukes or bring Saladin and Zara Yaqob in, because those guys have 3 vassals between them, which would suddenly mean a 6-on-1 war, and that's going to be a huge pain to fend them off while trying to conquer American cities given that most of them have defense satellites (SDI) against ICBMs. I should probably prepare a few dozen submarines with tactical nukes in case that happens.
Can I say what my next planned killed unit is? It's gotta be one of my own tactical nukes or guided missiles (probably the latter first because I have a small armada of them in Los Angeles) to soften up Lincoln's cities for my assault by numbers. I will need a large fleet of destroyers to protect against his fleet of destroyers, however. I'm a bit lagging in that area simply because he and I have a sizable land border for an archipelago map and I've been focusing on taking down neighbors that I don't have to build a navy for first.