Ran across this interesting brief video that talks about squatter cities in developing countries. If squatter cities are usually in the outskirts of major cities, will there be a time in the future when it will merge with the major cities? The other thing I wonder about are the environmental consequences of having cities grow via squatter cities. While wealth is accumulated within a city, is it healthy for humans to be living in such massive numbers in such a concentrated area? Is it healthy for wildlife for that matter?