Before a major San Francisco earthquake, thousands of sea lions disappear from the harbour. Did they sense the impending disaster? A century after its discovery, experts remain baffled by a mysterious medieval manuscript written in a secret code. Wha... (more)t secrets does it contain? And, while testing ancient mummies, forensic scientists find evidence of cocaine — a Peruvian product not found in Egypt until thousands of years later. Was there trans-Atlantic travel long before Columbus?