The flying island in Castle in the Sky is called Laputa. In the film, it is a legendary airborne kingdom containing advanced technology, ancient ruins, and a massive tree at its center.
Pazu first learns about Laputa from a photograph taken by his father, who was ridiculed after claiming to have seen the island. Sheeta’s crystal pendant helps confirm that the legend is real, because she is descended from Laputa’s royal family. Together, Pazu and Sheeta try to reach the island while being pursued by Muska, the army, and the air pirates led by Dola.
Hayao Miyazaki’s 1986 film draws on the flying island in Jonathan Swift’s 1726 satire Gulliver’s Travels, though Ghibli’s Laputa has its own mythology and technological history. The island also embodies the film’s environmental theme: its advanced machines are dangerous when used for domination, but its natural world survives after human violence.
Some English-language releases shortened the title to Castle in the Sky because “Laputa” resembles a vulgar Spanish phrase. The island’s name in the story, however, remains Laputa.