From The Art and Popular Culture Encyclopedia
The Walking City was an idea proposed by British architect Ron Herron in 1964. In an article in avant-garde architecture journal Archigram, Ron Herron proposed building massive mobile robotic cities, with their own intelligence, that could freely roam the world, moving to wherever their resources or manufacturing abilities were needed. Various walking cities could interconnect with each other to form larger 'walking metropolises' when needed, and then disperse when their concentrated power was no longer necessary. Individual buildings or structures could also be mobile, moving wherever their owner wanted or needs dictated.
- The four novels in Philip Reeve's Hungry City Chronicles include large mobile Traction Cities that travel across the world, devouring each other to gain fuel and other resources.
- A massive city travelling along equatorial rails around the planet Mercury is the setting for a minor part of Blue Mars, the last book in the Mars Trilogy of Kim Stanley Robinson. The city is pushed along by the minimal but extremely powerful expansion of the rails as the close-by sun shines on them (with the city always just staying within the planetary night), moving the city once around the planet every 88 Earth days. The same city is the setting of Robinson's early novel The Memory of Whiteness.
- There is a similar arrangement in Timothy Zahn's Heir to the Empire, where Nomad City avoids Athega's light by continually moving over the surface of Nkllon.
- In Eoin Colfer's book, The Supernaturalist, the futuristic "Satellite City" in space is described as one that has buildings with mobile capabilities, due to the needs of the life condition there.
- In Alastair Reynolds' Absolution Gap, vast cities circle the moon of Hela to keep the planet Haldora in view, in case "the Miracle" - the momentary disappearance of Haldora - will occur again. The mobile cities are called Cathedrals and are devoted to the worshipping of the Miracle, which they believe is God's message to humanity.
- In Christopher Priest's novel Inverted World a city on a "hyberbolic" planet is continually moved on rails to keep it at a particular location -- which itself moves -- where conditions are "normal".