Overview: Sharks have terrified people for centuries and deep within the forbidding waters of Mexico's Baja Peninsula may lurk a mammoth sixty foot monster. In prehistoric times, huge carnivorous sharks, more than twice the size of a great white, ruled the waves. Marine experts claim these giants went extinct, but evidence may challenge that. Meanwhile, frightened Mexican fisherman talk of being stalked by a "Black Demon"; and sailors report close collisions with a shark unlike anything that they have encountered before.