Petroglyphs are images created in rock by incising, pecking, carving, and abrading the rock surface. These rock carvings are found across the world and are often associated with prehistoric communities. The oldest known petroglyphs have been dated to about 12,000 years ago, and are thought to have been an early form of symbolic communication or perhaps a sort of “pre-writing.” What is the one continent on which petroglyphs have not been discovered? Discuss
Source: The Free Dictionary