Globalization is also marked by new means of wealth creation and distribution, inducing labor forces to move toward aggregations of capital most of which are urban. This process has touched off the largest migration in human history (18) . The 21st century has become the urban century as for the first time in human history more people live in cities than in rural areas. One component of this migration is cross-border, legal and illegal migrants seeking work. This pattern, however, is dwarfed by within-country migrations which have brought hundreds of millions of people into cities, now perceived as the critical nodes of global production, and therefore the locus of jobs. In many of these cities, especially the "newly large" cities of the developing world, or the mega-cities of Asia, living and working conditions resemble those of Dickensian England. At the current edge of the 21st century's world, industrialism coupled with urbanization has reproduced the social conditions of the 19th century. The unchecked growth of mega cities as survival harbors make them the new reservoirs for the lethal combination of poverty, crowding, insufficient sanitation, impure water and disease.