A startling discovery of 70,000-year-old artifacts and a python's head carved of stone appears to represent the first known human rituals. Scientists had thought human intelligence had not evolved the capacity to perform group rituals until perhaps 40,000 years ago. But inside a cave in remote hills in Kalahari Desert of Botswana, archeologists found the stone snake [image] that was carved long ago. It is as tall as a man and 20 feet long.