SwitchbladeNGC
Bird of Prey
I think that you should be able to have a chance (albeit a very small chance) of learning a tech from defeated enemy units that are more advanced than you. I go to school in Huntsville Alabama and there is atleast one company there that does Reverse Engineering (Taking apart enemy military hardware that was captured to see how it works or see how to make it not work in combat
). I think that would be a good Idea to impliment in Civ4. What do you think? Please forgive me if this has already been discussed. (and if so please point me to the thread)
