Floating City (science Fiction) - Earth

Earth

In Jonathan Swift's satirical novel Gulliver's Travels, Swift envisioned Laputa, an island city that floated in the sky. The island was suggested to levitate above the Earth by use of the force of magnetism. In the 1920s, Hugo Gernsback speculated about floating cities of the future, suggesting that 10,000 years hence "the city the size of New York will float several miles above the surface of the earth, where the air is cleaner and purer and free from disease carrying bacteria." To stay in the air, "four gigantic generators will shoot earthward electric rays which by reaction with the earth produce the force to keep the city aloft."

Laputa (although uninhabited) is shown in Hayao Miyazaki's Castle in the Sky.

Although Swift's proposal was intended as satire, Buckminster Fuller proposed the concept more seriously in the form of the Cloud nine (Tensegrity sphere) megastructure, in which he envisioned structural spheres that float freely in the sky, allowing passengers a migratory lifestyle and a solution to the depletion of Earth's resources. He proposed a 1-mile-diameter (1.6 km) geodesic sphere that would be heated by sunlight, functioning as a thermal airship.