Remember Green Pillars? Well, this one happens to be from the same basic terrain as that image. For some reason, either the camera was moved or the terrain was altered in my terragen files for Green Pillars, so even if I wanted to I might not be able to recreate that image. At that point, in addition to being confused about the files, I was also bored.

This prompted me to start fooling around with various things, from the camera to the terrain. I had it generate a new terrain on top of the existing one, along with messing around with the camera position. Finally I decided to see what the exposure setting did, and out popped something closely resembling what you have now.

I had to add in some texturing to make the right pillar look more realistic, and as an unintended effect (although it does look nice), it lit up the left side of the pillar along with part of the landmass behind it. Makes it look really nice actually.