Ancient petroglyphs on cave walls

Image 1. A cave drawing showing a spiral design carved into a piece of rock. Source U S National Park Service. Image 2. Drawings carved into a rock show animals and birds, what look like animal skins, large footprints with varying numbers of toes, and one human on horseback with what looks like a bow and arrow. Source P g a i m.

Sources: Courtesy of the US National Park Service; © Pgiam/istockphoto.com.