6. Consistent Quality
Think of the few great movie trilogies in film history and you'll notice a general drop in quality in at least one of the entries. The Star Wars trilogy started out with two masterpieces and ended with a very good but not quite great entry, and the same could be said about The Godfather series. Nolan's Batman movies likewise started and ended with two supremely entertaining yet flawed films, the Bourne Movies were consistent but never quite reached "greatness", and the same could be said for the extremely impressive Harry Potter series. Meanwhile the Lord of the Rings trilogy is arguably the only blockbuster trilogy in film history without a significant drop in quality between the first and last installment. While Return of the King does have its share of questionable moments, it also contains some of the most epic scenes in blockbuster history. Unlike most trilogies, which gradually expand into future installments depending on if the original is successful, The Lord of the Rings was essentially shot as one gigantic movie which was split into three parts and released over a period of three years. Since the film was shot roughly back to back to back, the whole series flows smoothly between its parts without any major changes in the quality of the work. The Lord of the Rings, by ending in such a spectacular fashion, clearly ousted Star Wars as the greatest trilogy of all-time and with three movies of such magnificent quality, it lays an overwhelming claim to the longest stretch of greatness, in terms of run-time, in cinematic history.