Dustin Mater is a Chickasaw artist who's fascinated by ancient rock art. He says these images resonate with stories he heard from tribal elders, which he uses as inspiration for his own art.  

Stephen Alvarez — a National Geographic photographer and founder of the Ancient Art Archive — has spent years documenting ancient rock art around the world. He takes Steve Paulson on a long hike in the Cumberland Plateau, where they find an "unnamed cave" with 2,000-year old engravings.