An Art History Geek Blog Post: Cave Paintings of Lascaux

Over 17,000 years old--this dun colored pre-historic horse adorns a cave wall in Lascaux, France.

Proof that the horse has inspired the artist for quite a long time.

and here's a cool site with tons of info on the Lascaux caves:
http://www.culture.gouv.fr/culture/arcnat/lascaux/en/