Steven Moffatt and Mark Gatiss's modern re-imagining of Sir Arthur Conan Doyle's Sherlock Holmes mysteries has been huge hit globally. It's won three Emmys and has been broadcast in 180 territories. Benedict Cumberbatch and Martin Freeman star as Holmes and Watson, and many of the famous characters from the books appear across the four (depressingly short) seasons. Ironically, the show's success and that of its leads means it's virtually impossible to get them together to film more episodes, though it may happen if we're lucky.