John Snow made a great impact toward science, since he caused the germ theory to replace the miasma theory in terms of public health epidemics. But in addition, by causing cholera to subside in London, he also created the hope of sustainable urban dwelling. Soon, we may live in what is known as a “planet of cities”.

However, disadvantages of urban living still prevail. The disaster of 9/11 occurred in New York City, killing many. In addition, the death rate of people affected by diseases is much higher in New York City than it is in say, a small town in Montana. Such disadvantages are not due to technological advances, however; the 9/11 terrorists used simple tools(knives) and the problem of bacteria is as old as the beginning of time.

Even though New York City is relatively safe for having such a large population, it has to become safer both in terms of diseases and danger in order for the “planet of cities” to become successful.