/documents/CivilizationIV/CustomAssets. If you don’t want to worry about installing files in the wrong place, download AlanH’s excellent Mods Installer, which automates the process. Mods in the CustomAssets folder will be loaded for every game. Other mods are installed in ~/Documents/Civilization IV/mods. To play these, click “Advanced” on the main screen and then click “Load a Mod.”
I am in love with this mod. I installed it the first day a Mac-friendly version became available, and I haven’t looked back since. I never especially liked Civ’s somewhat cartoonish terrain, which BlueMarble fixes by using satellite images of the NASA BlueMarble Project as the basis for a beautiful, realistic environment. It truly is a stunning mod, and makes you wonder what Firaxis was thinking. Low-res and high-res versions are available, depending on the capabilities of your machine.
Ethnically Diverse Units
Also one of my favorites, this mod gives each civilization units a distinct look. Africans, Arabs, Asians, Indians, Persians, Mongols, Egyptians, Romans, and Greeks are represented. Not to mention the six flavors of modern infantry and five castles.
Better Ship Scale
Annoyed by the fact that your destroyers are smaller than your frigates? Then Better Ship Scale is for you. It gives ships a more realistic size given their technological sophistication. A version of this mod, Better Ship Scale Fleets, remakes many ships as fleets of three, much like land units can be groups of three.
ScenariosIn general, most scenarios should work just fine as long as they weren’t made with the SDK. To install them, place the mod in the Mods folder of your main Civilization IV folder and the “worldBuilderSave” file in the public maps folder.
The Ancient Mediterranean Mod expands the classical time period. If you like fighting with sticks and arrows, this is your mod. It features over twenty ancient civilizations, including the Carthiginians, Myceneans, and Minoans. Want to worship Apollo? Now you can. This mod is the Caesar III of Civilization.
The Age of Discovery Mod starts in the year 1492, leaving the New World up for grabs. Play as the King of France, Spain, the Ottoman Empire, or start in the Americas as the Mayans or Incas. This mod plays without a hitch, but you may notice some code in “Sid’s Tips” technology rollovers. It won’t affect gameplay.