Have you ever heard of that word before?
It's a series of waterfalls in Switzerland, but that's not what the word is known for. In the short story, the Final Problem, this is the location where Sherlock Holmes had his final fight with his arch-nemesis Professor Moriarty. They had been clashing for years before and their largely intellectual fight was finally brought to close quarters when Moriarty sent several men to kill Holmes. Holmes lured Moriarty to Reichenbach Falls and they both tumbled down. Mutually assured destruction. But Sherlock Holmes doesn't die. He returns to 221B three years later.
What's interesting about this word isn't any event that made it into the Holmes Canon, it's what was kept out. When Arthur Conan Doyle wrote the Final Problem, he meant to kill Sherlock Holmes. The detective he created had gotten too out of hand for him. He was constantly trying to create new mysteries and the stress had become overwhelming. He wanted to stop writing these silly mysteries and write more historical novels. It was only his fans' outcry that forced the author to bring back Sherlock Holmes.
With any mention of Reichenbach in a Sherlock Holmes story, fans know what they're going to get. The beloved hero of the tale will take a fall. And it's heartbreaking. Even though we know he lives, it's gutwrenching. Reichenbach represents a dark time, a necessary sacrifice, a period of hopelessness and an eventual triumph. Sherlock Holmes's dearest friend John Watson, thought he was dead for years. We suffer along with him because in real life, Sherlock Holmes really did almost die.