What actually caused the Maine to explode -- a Spanish mine or an accident in the ship's forward ammunition magazine -- is still a mystery. A Congressional investigation at the time was inconclusive, but that didn't stop the yellow reporting. The first story in Pulitzer's New York World carried a banner headline that left little doubt about who was responsible: ''Maine Explosion Caused by Bomb or Torpedo?'' The Journal published a diagram of what it called a secret ''infernal machine'' that struck the ship like a deadly torpedo -- apparently the figment of some journalist's imagination.