BURGOS, MEXICO—Nearly 5,000 paintings have been discovered in 11 different sites in northeastern Mexico, in an area thought to have been uninhabited during the pre-Hispanic era. More than 1,500 of the paintings were found in one cave alone. The images depict people, animals, and insects, as well as an atlatl and abstract objects, and are thought to have been created by at least three different groups of hunter-gatherers. “We have not found any ancient objects linked to the context, and because the paintings are on ravine walls and in the rainy season the sediments are washed away, all we have is gravel,” said Gustavo Ramirez of the National Institute of Anthropology and History. Scientists will attempt to date the paintings’ pigments.