Non-Gaussian Distribution: City Size

One example of a set of data that does not follow the Gaussian distribution is the ranking of city sizes.  After the largest city is accounted for in a country, the remaining cities gradually decrease in size.  This ranking follows a power law and can be explained using the Pareto distribution.  The graph of population vs percentage of cities would have a long tail skewed to the right due to the fewer number of cities with very large populations.  It does not have the bell curve seen in a Gaussian distribution.