Kingdoms is the most content-rich expansion ever produced for a Total War game, with four new entire campaigns centered on expanded maps of the British Isles, Teutonic Northern Europe, the Middle East, and the Americas. In Medieval II, you were only given a tantalizing glimpse of South America, but in Kingdoms, vast tracts of land in both North and South America have been opened up for you to conquer. All-new factions from the New World are also now fully playable, including the Aztecs, Apaches, and Mayans.
One of the best Total War games.
As usual with Total War games, M2TW is better when used with Mod.
And because M2TW is particularly mod friendly, you can find absolutely awesome mods such as TATW (Third Age Total War), Broken Crescent, Rusichi Total War, etc.