Go to Program Files\Civilization III\Art\Terrain and rename the image "TerrainBuildings" to something like "TerrainBuildingsOriginal".  Then put the new image from this zip file there.

I only did the forts, the other buildings are the original ones.

I was attempting to make it easier to see if units were actually in forts without having to strain my eyes.

Let me know what you think.

Dan
Alias Bonaparte