World-building is essential in almost every genre of film, as it provides elements that make a story's fictional setting feel real and lived-in—ranging from geography to history, internal world rules to every detail imaginable. However, very few genres demand world-building as powerfully as fantasy does, and fortunately, there are numerous fantasy masterpieces that can be counted among the best films in the genre, all boasting extraordinary world-building. Whether it's a well-designed magic system, carefully crafted mythological creatures, or simply incredible sets and production design, there are countless ways to make the world-building of a fantasy film successful. From classics like The Dark Crystal to modern masterpieces like Pan's Labyrinth, these ten masterpieces are proof of how crucial world-building is in this genre.

In the 2020s, only a handful of fantasy films can be considered true masterpieces, and David Lowery's The Green Knight fits perfectly into this category. Adapted from the legend of the name in Arthurian lore, the film is an effective art-house adaptation of the original story's core thematic concerns—chivalry, masculinity, mortality, and the cost of honor. It unfolds at a slow pace and certainly doesn't cater to all cinematic tastes, but it stands as one of the most exquisite fantasy films of the decade. Thanks to Lowery's quiet directorial methodology, the world of The Green Knight emerges as a blend of realistic medieval elements and beautifully surreal segments. While it may have a simple world-building, it creates such an effective dreamlike atmosphere that it's hard to resist.

The Dark Crystal, directed by Jim Henson and Frank Oz, was introduced as the first major live-action film with no human actors, instead presenting characters brought to life through legendary animatronics and puppetry. Over 40 years later, the result is still as impressive as it was in 1982; aware that this striking appearance is now mixed with a tremendous sense of pure nostalgia. It is one of the best fantasy films of the 1980s, and while its story may not be its strongest aspect, the world-building is so phenomenal that it becomes much easier to overlook the existing narrative flaws. The film's unique non-human aesthetic elements give it a vibrant, textured look that many other films in the genre do not share, and the deep lore and mythology of the Thra universe, needless to say, is captivating.

Studio Ghibli, in general, and especially Hayao Miyazaki, produced incredible works throughout the 1990s, but there is truly no question about when Miyazaki's career in the 1990s came to an end. It must have been when he released Princess Mononoke in 1997, an animated masterpiece still remembered by the public as one of the greatest and most mature animated films of the 20th century. It is one of the best war-fantasy masterpieces ever made, thematically rich with a story about the destructive conflict between nature and industrial civilization. Set in a semi-fantastical version of historical Muromachi period Japan, the film draws elements from this historical era, Japanese folklore, and Miyazaki's imagination to create one of Ghibli's most atmospheric and engaging worlds.

Labyrinth was met with mixed reviews and a lukewarm box office reception in 1986. Written by Terry Jones of Monty Python and directed by Jim Henson (in fact, it was his last feature film), it has since become a genuine cult classic musical.