Which US cities are divided into distinct parts?

Two American cities stand out in their development in dividing into distinct parts. These cities run the gamut from extremely urban to true suburbia within city limits and incredibly almost a "rural fringe" (vastly disappearing). In addition, these cities have topographies that create zones that are distinctive. They are, of course: • New York: Five boroughs, only two of which (Brooklyn, Queens) have a land boundry. Created in an unusual way through the establishment of Greater New York at the end of the 19th century, NYC became an amalgamation of the original NYC (Manhattan) and 4 neighboring counties. One of these, Brooklyn, was a great city in its own right and still retains its distinctive city-like atmsophere today. Issolated Staten Island is a place apart. Queens not only is set apart like each of the boroughs are, but many of its communities are more like villages or suburbs of their own. Such examples can be found in other boroughs as well. And ultimately today, there is the difference between Manhattan itself and the other four boroughs. Los Angeles: Where NYC used an act of the state legislature to create a greater self, LA used availability of water to fuel its expansion; it was able to swallow the San Fernando Valley in one swoop. No US city has the physical divide that the Santa Monica Mountains creates in LA. The Valley was and is a world removed from "LA Proper" and the differences created the secession movement of the 90's in the valley. Smaller in scale, LA reached southward with a narrow strip to aquire the harbor areas like San Pedro, adjacent to Long Beach. LA, more so than other cities, developed as a series of separate towns that spread together and join. Thus areas like Encino in the valley, Brentwood in the hills, Venice on the coast, and Hollywood in the heart of town have always had their own identies. I doubt that any other cities in the US can compare with NYC and LA in the diversity of these environments, but are there others that share some of New York's and Los Angeles's characteristics? Which cities have either the geogrpahic/topographic differences and/or the city-to-suburbia-within-city-limits characterists of New York and LA? What are the distinct areas of those cities and is the distinction geographic/topographical or is it based on the continum of urban-to-rural?>