Since the begin of this forum, severals people have post picture of cave painting. There is around 350 known cave painting sites in Europe (mostly in Spain and France). The oldest ones are around 40 000 years old.
Moreover, caves could offer temporally selter early game when you are still a nomadic tribe (like it was in real life).
Hence I wonder if cave painting and habitat will be in the game? Will it be possible to (re)creat existing cave painting (a bit like wonder momunents)? Is it a hidden goal in the indiegogo campaign?