EweezE
Dog Soldier
I think you should be able to build moats in Civ. After you've built walls and castle, moat should unlock. It would incur a crossing river -25% to any attackers of the city. It could not be built by hilltop settlements since they already have a natural 25% defense bonus. It gives the flat ground cities a better chance at defending themselves. It would even encourage amphibious promotions for attacking units. Moats would add more strategy and look really cool in game.. I don't see how they (Firaxis) missed this. Maybe it will make the cut for Civ5, hopefully.