Strange mounds in Transylvania might pinpoint the location of the tomb of the bloodthirsty tyrant believed to have inspired Dracula; a mysterious ancient city is discovered on a coral reef; images of a plane crash set off a hunt for a drug lord.

A strange structure shaped like a giant shark might point the way to a lost civilization's fountain of youth; a massive hurricane heads toward Florida but something unexpected is in its eye; bizarre marks across the eastern U.S. leave experts baffled.