>If you've not watched the Herzog classic "Cave of Forgotten Dreams" - I highly highly recommend it - the paintings are amazing.

Especially if you have a chance to see it in 3D and/or on a big screen. The paintings incorporate the curves and contours of the cave walls to represent things like the bulging of muscles or even to simulate movement and that's difficult to convey in 2D. They did a remaster and IMAX re-release earlier this year and seeing it that way makes the images even more magical.