the city

Prompt:  5s a huge city, one end of which moves forward by disassembling its other end, so it inches across a huge dying-Earth landscape. immense city, rife with deadly danger and occasional nakedness city exists three miles high and countless miles long encompassing tens of millions of people displaced from Earth. Structors (the builder's guild) deconstruct the "Tailend" of the city and rebuild the "Frontend" in a sort of glacial urban march from the mountains to the sea over 30,000 years. Multiple generations of folk living at the Tailend are obliged to pack up and relocate to the Frontend. However, entropy and decay has set in. Machines cease to function and fall into disrepair and society slowly loses technological knowledge with each successive generation. A voyage through a self-contained, moving that house all of mankind. An ancient city is migrating across the land. When Brann had to flee the dilapidated back of the city, which was being torn down, he explored forbidden and forgotten routes and shafts that were as mysterious as the path and destiny of The City itself. Poking around lost chambers and basements of an ancient, self-enclosed, single-building city of ginormous size huge city that is thought to contain the whole world by its inhabitants. I never quite worked out the dimensions but it's miles across and hundreds of levels high, and tens of miles long. Generations of people have lived in the city such that nobody remembers any other way of living. Around every 10 years the 'tailend' section of the city is demolished and its occupants go on 'pilgimage' to the other end of the city, where the materials from the demolished section are used to build a fresh new section. This continues generation after generation such that the city is slowly moving across the landscape. Nobody remembers why. Everything has started to decay and breakdown, and there are remnants of technology that nobody understands or can repair.