Sherlock Holmes was a famous fictional detective created by Sir Arthur Conan Doyle. Holmes lived at 221B Baker Street in London with his friend and partner Dr. John Watson, where they solved mysterious crime cases using Holmes' skills of careful observation and deductive reasoning. Some key facts about Holmes include that he often used drugs like cocaine and tobacco, had his arch-enemy Professor Moriarty, and his former residence is now a museum for fans of the Sherlock Holmes stories.