  Expected urban population doubling calls for a compelling theory of the city.
Random walks and diffusions defined on spatial city graphs spot hidden areas of
geographical isolation in the urban landscape going downhill. First--passage
time to a place correlates with assessed value of land in that. The method
accounting the average number of random turns at junctions on the way to reach
any particular place in the city from various starting points could be used to
identify isolated neighborhoods in big cities with a complex web of roads,
walkways and public transport systems.
