Chauvet Cave, France
This is found in the famous Chauvet Cave, a cave with the oldest known human cave paintings.
Ancient culture has always fascinated me, and this image can be found at the ancient entrance to an old cave that leads to what can only be described as a Paleolithic art gallery.
I consider this Graphic Design as this is the first image anyone coming through the cave to where the ancient cave once was will see, almost like an indication that they were going into a cave claimed by someone. I see this as the earliest example of a poster or sign with at least some form of reason or design intended.