Using the displace modifier I creating my landscape, after creating a photoshop texture as the base of my displacement for the landscape this is the result:

I then coloured in the texture using images from the internet and default textures in photoshop, I added this texture to my landscape model.

Here is the textured landscape I will soon be adding a city to this with trees and a skybox:

Here is the cityscape I have created to add to my enviroment, I will be making this city looked destroyed to match my apocolyptic theme and plans.

Here is the destroyed city I have added to my enviroment, to do this i used the noise modifier to make the buildings look unstable and rotated most of the building on there side and under the ground.

Here is what the enviroment looks like with trees added to get these trees I used the AEC Extended Foilage object type to add premade trees, I have rotated to trees as if they were knocked over as if a earthquake as just hit. (explaining the destroyed city)
