This is sweet. I love how you've managed to keep such a strong connected between the blue and orange/red color on the left picture. Where have you studied art by the way? (If you have gone to any academies or schools) - Some people are self-taught too, but this is really awesome.
Lovely work on the caves, Dan. There are photos in my newest National Geographic Magazine (came a couple of days ago) that these could have been referenced from. Just one of those interesting coincidences.