One of the best underground Civ 4 mods ever, period. Most of the images are gone, the creator/creators haven't checked in many moons, and the links to download this mod are drying up. This is simply an upload by a fan, so that others can hear of the genius of this mod, get proper download links, and so on.
My favorite is the Iraq one.
I'm serious, the building and marine replacement are really good.