Nah, I didn't make these(but these are true maps that are being playing online today-the first one is actually a Capture the Flag map)
http://www.unrealplayground.com/feature.php?id=1799
... although I do have a few nice desert maps and a decent asian themed one but I can't find a screenshot. These were actually made for Unreal Tournament and there is an editor included with the game Unreal Editor 2.0 built upon the unreal engine.
You actually have to paint the terrain; meaning you create it hills, valleys, ridges, then you go back and smooth it out or rough it up, create rivers, lakes, etc and add volumes for water, lava, goop, you then can go over and layer multiple textures to create depth and color...you can even make the terrain slick like ice or sluggish like sand and depending on the texture you use - the sound is created dirt, rock, sand, metal, etc. It changes as you change terrain. Meshes are created the same way .... trees, bushes, plants, urns, buildings, etc. You then go back and optimize using blocking volumes, fog, and other techniques so you don't see the whole world at once and kill your frame rates.
I think any of these will run on a GeForce 5200 and up. I really have a lot of fun creating maps that are still being played on servers today. Anyway, I was just dreaming and I am sure JM has plenty of staff......plus I wouldn't want to work for them......all the mapping I have done is for free and is used freely by the public.
I did find this screenshot of a map I made some time ago. Not one of my best but anyway you get the idea. It would just be so easy to integrate some new areas into the ISRO world without having to wait for JM.

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