Cave writings dating back 40,000 years from across Europe reveal the common use of similar symbols that linked ancient peoples and cultures. Genevieve von Petzinger explores this in “First Signs” by delving into the origins of cognitive symbology. While visiting caves such as Chauvet, Lascaux and Niaux, he observes geometric symbols, crosses and spirals. Although they are not figurative, they have cultural significance across regions. (Image: Wikipedia)