It's 17,500 years old. And, AFAIK, my friend and muralist extraordinaire Andrew Johnstone is the first man (in modern times) to recognize the Cave at Lascaux for what it is: Fantastic images of animals, yes, but grouped according to star patterns dictated by the night sky of the ancient summer solstice (Northern Hemisphere) . See, explore, ENJOY:
http://adjohnstone.com/STARWALLS.html