How large would a city be if you squeezed the entire world’s population of 6.9 billion into that city? Tim De Chant took a look at the geographic range of different theoretical cities based on the current population densities of Paris, New York, San Francisco, London, Singapore, and Houston. Against the backdrop of a outline map of the United States, De Chant mapped out how many states would encompass each city.
A theoretical city based on Houston, with the lowest population density in the group, takes up the most geographic space, extended over what seems to be two-thirds of the U.S. and occupying almost 1.8 million square miles. The smallest theoretical city, with almost 128,000 square miles, was based on a population density equal to Paris.