I know this might seem like a noob question and I might be overlooking a setting somewhere, but i seemed to have looked everywhere and can't find out how to enable terrain detail, such as forests, tile upgrades, etc. They don't show up on my map, but when I hover over the tile it tells me they are there. Cities still show, but they are always very small. If you want a picture please ask and i will upload one.

My friend is having the same problem. Everything sounds fine except that the forests and jungles are not showing. I've got him to update his Gfx drivers but that didn't fix it. I thought it might have been a shortcut he hit but like super_serge I can't seem to find anything that would do that. Plus he said it was like that as soon as he played it.

I don't know all his computer specs but he's a few main things.
CPU: Intel 3.0Ghz dual core
Gfx: ATI Radeon x1900 (I have a Radeon x800, no problems)
Ram: 1ghz OCZ
Mobo: Asus P5LD2
OS: Win XP pro

Make sure you're using the authentic executable.

Yep, I told him to try use the original .exe and his CD and it works fine. Thanks!

Same Problem with me (at the beginning).
Mine was much worse than yours.
I have notebook with Ram 512 MB, Video Ram 32MB (Geforce Nvidia 420 Go), processor 2.4 GHz.
I have updated latest driver for VGA driver (from NVIDIA), my problem not solved. I have tried downloaded from omega driver ( you shall try this, search Google for omega driver & installed for quality ), but still my terrain still black and blank.
At last I've downloaded civ4 path V1.61.. ammazing :) it works..