5/4/1891 Meet me at the Reichenbach

May 4, 1891.  On this date there occurred the most famous event that never actually happened (well... there are more famous ones, if you agree that all religions can't be be true).  In Arthur Conan Doyle's story "The Final Problem" Sherlock Holmes grappled with Professor James Moriarty at the top of Reichenbach Falls in Switzerland.  Both fell to their death.
 
But one of those deaths was cancelled, due to popular demand.  How often does that happen?

Illustration by the great Sidney Paget.