That is the kind of things I wish I could recreate - the randomness and chaos, and yet seemingly orderly landforms that Nature alone creates. Whenever I see those in one of my renders, it's due to too much of something - displacement, warp, fractal parameters, you name it. It'd be great to, say have randomly spiked towers that wouldn't come to a sharp point - some way to make them look like you did something "bad".