A plague that wipes out 25 million people in three years. A disease that kills its victims within hours of the symptoms appearing. A flu that makes its sufferers turn blue before drowning in their own lungs.
It sounds like the stuff of science-fiction movies, but for centuries, these horrid diseases were very real (in fact, some of them could still pose a threat today). What are they? Read on as we uncover the seven deadliest diseases in history.