A special action that cities are able to take. Doing so will completely destroy the city and convert it into a new settler unit. All expansions, districts, and city improvements will be destroyed in the process. However, one must have full ownership of a city in order to take this action, meaning that cities that have been conquered in war must be owned by the captor for a number of turns before this action can be taken.
Whether the result of an impetuous colonization decision or an impending attack, sometimes everything in a city must be destroyed and the population removed.