Has there ever been a greater trilogy? The Godfather, monumental as its first two installments are, peters out in Part III. Same with Alien and Terminator. Back to the Future and Indiana Jones more or less land the plane, but the follow-ups never hit the heights of the originals. Richard Linklater’s Before trilogy and Krzysztof Kieślowski’s Three Colors trilogy are masterpieces start to finish, but they lack the operatic scale and mainstream appeal of, say, Star Wars or Lord of the Rings.