I'm sure it was blind rng chance and not actually the AI being "smart" but I finally had a game against the AI that at least for awhile felt like a move by human players or coalition of human players. Usually play apollo or Soyuz but was going for the build all wonders achievement, so started game one level below Soyuz. Was hardly expecting a challenge. To my surprise though, fairly early on - turn 125 or so I think - the entire AI world ganged up on me and declared war -each one said something to effect of if I don't take you out now, will be too late if you become a runaway. Those weren't the words of course and wish I'd screenshot it but it was clearly a message saying basically better take you out now before you become a runaway I'd played peacefully with all AI except one - the one that shared my landmass and I eliminated, leaving 4 AI players and me. Had only built 3-4 wonders and while was leading score, wasn't by huge amount. Anyway, the coalition of AI must have all signed open borders because the entire AI horde, like some massive rainbow coalition with units from 3 of the 4 AI in first wave, came against my one lone city outside my landmass, the AI I'd knocked out had gave it to me in one of our peace agreements before I eliminated him. Cut off from my landmass and no phasal transporters yet, I had only enough energy to buy a few units since I'd broken my CiV habit of hoarding gold as in CBE usually stockpiled energy is a waste - might as well rush buy buildings as you get the excess energy. Except of course when you now have the entire world going ape on you. And wished you'd hoarded energy. Again, I know it wasn't the AI being really smart but some weird fluke of rng and game triggers, but in this one rare case, it was a good backstab move by the entire AI coalition - just like human players would, they basically pm'd each other and whispered - hey, this guy just took over his landmass - if we give him too much time he's going to spread like a plague. Let's all declare war on the chump and after we dispose of his corpse, then we'll go back to hating each other. They took out my city, I renamed it to Alamo just before it fell because that's what it sure felt like. And for 50 turns or so it was pretty challenging fending off the AI world. The only saving grace was that as usual, AI naval assaults across water is like the blind leading the blind. So once they lost most their units in the lemmings wave it was game over. But still, really felt surprised in one of those rare BE games where the AI actually did a pretty human backstab lol.