Ancient cave art unearthed in Mexico

By Megan Gannon, LiveScience In the mountains of northeastern Mexico, archaeologists have unearthed thousands of ancient paintings on the walls of caves and ravines from a time before Spanish rule.The rock art offers rare evidence from native cultures living in the area around the Sierra de San Carlos, a mountain range in Mexico's state of Tamaulipas, researchers say.Almost 5,000 of these pain….