A societal phenomenon found on some, although by no means all, megastructures. Megastructural Migrations or Moving Days as they are more commonly called, usually take place on those macrostructures with populations occupying only a small percentage of the structures entire habitable area/volume.
Every few centuries, the entire population will transport their entire civilization to a new area of the structure, leaving their previous habitation area 'fallow'. The new area of the structure has been prepared in advance for new inhabitants, usually by a small army of environmental design and construction specialists working in secret for several decades or even centuries. The new area of habitation is designed to be comfortable and safe (mostly), but with an entire range of new designs, environments, and 'artistic touches' intended to fill the newly arrived inhabitants with awe, wonder, and amusement for years to come.
Moving Days generally last for a decade or more and are almost always preceded by announcements and reminders of the upcoming Migration for at least that long in advance. Once the last of the inhabitants have removed themselves from their old habitations, a new group of designers arrives, emplaces privacy fogs and projectors, and sets to work on preparing the fallow region for new inhabitants, perhaps centuries in the future. Being accepted, or better yet invited, to take part in the redesign of a major habitat structure can make the reputation of any aspiring designer. Messing it up, or worse yet, earning the dissatisfaction or displeasure of the inhabitants, can earn one embarrassment and ridicule for centuries.
Typically habitats choose to take up the Migratory lifestyle either by a vote of the general population or at the discretion of their ruling AI. Information informing any potential visitors or new immigrants of the change is made freely available on the Known Net and those inhabitants who choose not to participate in the Moves are allowed to emigrate elsewhere without prejudice.