Cities always contain a large portion of poor residents. This might condemn large metropolises as aggregators of squalor, but “poverty in cities from Rio to Rotterdam reflects urban strength, not weakness” (70). Thriving urban areas attract the rural poor, who tend to improve their fortunes and move up the socio-economic ladder; their good results attract yet more rural poor, who, in turn, begin their own economic climb.

A city that improves conditions for its poor tends to attract more poor people. This is a sign of success, not failure. The many businesses in a big city, with their various types of jobs, provide opportunities for poor farmers, many of whom have little talent for agriculture but discover a flare for machinery or pastry-making or sales.

An urban transit system’s stations tend to become surrounded by poor residents because the stops give them a nearby source of inexpensive transportation, especially to their places of work. If the poor flock to a particular place, it’s because that place offers them advantages and a way to move up.

The hills around Rio de Janeiro, Brazil, house shantytowns called favelas. Runaway black slaves in the 1800 established the first such settlements; in the late 1890s, unpaid soldiers set up the first of the huts and shanties seen today and lately occupied by arrivals from rural areas.