add Mexico City

Mexico City has a pretty strong form of administrative subdivision, maybe relevant to this project. Most day to day local government happens at the delegación (borough) level. Personal identification of the residents as belonging to a particular borough is probably a bit less than it would be in New York but has some interesting aspects: for example Cuajimalpa or Coyoacán are far enough from the center and have enough of their own centers of gravity that they have pretty distinct identities from the rest of the city. I don't know enough about London or Tokyo to judge how analogous their subdivisions are but politically the delegación is very much like an NYC borough (if not stronger), and socially a bit weaker.