It's not just the physical appearence of the carvings although that has a lot to do with it. Ketley is one of those special 'within/without' places.
I suppose were straying into the territory of 'meanings' here, but I know I'm not alone in the idea that the carvings may reflect something endogenous..if that is the right word. The way some of the channels run into the rock face parallels other sites around the world and may express ideas of entering another dimension.
Lets just say , it's the vibe of the place.