When a "neighborhood" is thought of to have a much smaller area and than is designated by most newspapers, other publications, travel websites, as well as philistines, that is geographic diversity.
While metropolitan areas are usually the antithesis of geographic diversity, such metropolitan areas as the San Fransisco Bay area, Hampton Roads VA, the Tampa Bay Area FLA, Allentown/Bethlehem/Easton PA/NJ, Scranton/Wilkes-Barre/etcetera PA, the North Carolina Research triangle (Raleigh/Durham/Cary/Chapel Hill/Wake Forest), as well as any "tri-cities," "quad-cities or any other metropolitan area domminated by multiple cities are good examples of metropolitan areas which contain geographic diversity. Any smaller or average sized county which contains multiple towns with their own identities contains geographic diversity (on the other end, merged city/county governments such as Louisville KY are geograpically homogenous). Any state, provence or small country which is domminated by multiple cities, or at least may lack one single primate city (and the identityless sprawl surrounding it) are also geographically Diverse.
Geographic diversity means being able to go from one town or city to another and then another while travelling just a short distance.
In a large border city, one will often find geographic diversity on the other side of the said boudary.
People simply don't start towns anymore, just suburbs.
There are no suburbs, only sprawl, edge cities, and towns that have been imperialized.