The bar graph shows the populations of different places. Bar graph showing the peak population of Rome compared to modern U S cities. Population is measured in half millions. Boston is over 500,000; Jacksonville reaching almost 1,000,000; San Francisco is even with Jacksonville; Ancient Rome is 1,000,000; Philadelphia is a little more than 1,500,000; and Chicago is almost 3,000,000. What is the best title for this graph? Population Statistics for the Largest Cities of the World Population Comparison of Ancient Rome to US Cities Population Statistics for the Citizens of Ancient Rome Population Comparison of the Smallest Cities in the World