The LOTR mod will automatically modify the game and change several units to look like those from the Lord of the Rings.
In this modification pack, you will also be given some custom-made LOTR maps; Amon Hen, Moria, Helms Deep (preview image), Minis Tirith, and may more!
You can see the wonderful work below of the stronghold-knights.com team below.
Retaking of Osgiliath
My future ambition is to somehow change the actual game campaign to this, but let's see how you like this first :)