Gulliver's Travels is one of the great unread classics of literature. Most folks know the story in some basic way. They know that a man ends up shipwrecked on a distant land in which he is a giant and is surrounded by tiny people Lilliputians. Some folks even know that the man later ends up in a land of giants in which he is the tiny person. But few know that he also travels to a land of besotted intellectuals and aged immortals, and later to a land where horses rule and people are called "Yahoos". All that said, the story has often been seen as ripe for cinematic adaptation.
The Fleischer Brothers saw the story as a vehicle to elevate their cartoon studio and remain a viable competitor to Disney which had altered the animation landscape with Snow White. The Fleischers were given enough money from Paramount at last to make the kind of large-scale animation which might compete. The adventures of Gulliver seemed likely and we get the studio producing a handsome bit of animation, which despite its incredible charms fell somewhat flat. Here is a delightful link with much more about the classic film.
Some few decades later, the team of Charles Schneer and special effects guru Ray Harryhausen turn their Dynamation engine on and try to bring the tale of the classic to the big screen with live actors in The 3 Worlds of Gulliver. Well to begin with, one of the three worlds is the rather realistic world of England, so we're left with Lilliput and the land of the giants Brobdingnag. Kerwin Mathews is sufficiently appealing in the title role as a doctor seeking to make his fortune so that he and his love Elizabeth can live in some level of comfort. He ends up in Lilliput by himself and later Elizabeth turns up in Brobdingnag. It's all rather confusing really, as this is the least of the many movies made by Harryhausen. For one thing, there is only really one creature, a crocodile that Gulliver dispatches with relative ease. The use of forced prospective and other techniques is fine but nothing really different than what was seen in other movies.
All in all, the epic of Gulliver, despite its appeal hasn't really been brought to the screen with the vigor it needed to make it work fully.