I am posting this link which came from the CoastZone E-Newsletter. Here is a snippet from the email.
Today in Strangeness:
On this day in 1940, near Montignac, France, a collection of prehistoric cave paintings were discovered by four teenagers who stumbled upon the ancient artwork after following their dog down a narrow entrance into a cavern. Tour the cave online.
Lascaux
Who knows maybe Grok painted some of these!