The chaotic growth of today's cities can no longer be ignored. The great challenge is how to improve the quality of urban life by ensuring harmonious growth. Cities can--and should--learn from the experiences of other cities with similar characteristics. This effort requires not only the participation of urban planners but public health and environmental experts, politicians, and fundamentally, the communities themselves. Only when these actions are carried out will it be possible, perhaps, to reach that almost ideal situation heralded by Hippocrates some 2,600 years ago: a balance between the human organism and its environment.

When observing the chaotic, burgeoning growth of the modern city, the more erudite of urban planners will reminisce wistfully on how different it is from its ancient Greek counterpart, the polis, which Italian architectural historian Leonardo Benevolo once described as "dynamic but stable, in balance with nature, and growing manageably even after reaching large dimensions."

The rapid and uncontrolled sprawl of today's cities breeds anxiety not only among urban planners and architects. Experts in the field of public health are alarmed as well, for the apparent randomness of the urban dynamic is robbing the population of its basic health and well-being through unregulated environmental pollution, shrinking green areas, inadequate housing, overburdened public services, a mushrooming of makeshift settlements on the outskirts lacking in both infrastructure and services, mounting anomie and the sheer numbers of neighbors who do not know neighbors.

Beijing, a city of over 17 million inhabitants, exemplifies this social alienation. Until the early 1980s, the Chinese capital was constructed as a multitude of siheyuans, or one-story complexes built around a common courtyard that were inhabited by three or four families who shared a single kitchen and water spigot. These courtyards were connected by narrow streets called hutongs that formed a grid from north to south and east to west.

This open structure greatly facilitated contact between neighbors, encouraged the sharing of resources, fostered relations between contiguous families, and enabled the elderly to care for children and share with them their passion for songbirds. Because of these characteristics, these almost idyllic structures were described as "collections of small rural villages."

Until the mid-1980s, only a few skyscrapers disrupted the harmony of the landscape. Today that panorama has the look and feel of the ultimate modern city, where, with few exceptions, these "small rural villages" have been supplanted by sterile, towering skyscrapers. This striking change is not limited to external structure; it has also dramatically altered the fabric of human relations.

Physical isolation has led to an increase in crime, destroyed the local sense of solidarity, and contributed to the fragmentation of what were once cohesive family groups. As the distance between home and the workplace has also increased considerably, workers now find themselves devoting what was once valuable family time to exhausting commutes in overcrowded buses or subways.

According to Chen Xitong, a former mayor of Beijing, "the capital is growing increasingly ugly and it is steadily losing its Chinese character. Most of the modern high-rise buildings, with their boring concrete facades, look like dominoes set down in the landscape without plan and without imagination."

This situation, of course, is not limited to China. In many Latin American cities, old colonial mansions of considerable historic and architectural value are being replaced by huge apartment buildings unrelated to the character of the neighborhood. A new kind of war is being waged in cities throughout the world: Esthetics vs Profits.

- In this blog series, Dr. Cesar Chelala explores the many challenges presented by urbanization, the impact of urban migration, challenges to health, and challenges of providing clean water. - Ed.

Cesar Chelala, MD, PhD, is an international public health consultant and a writer on human rights issues and foreign affairs.