This map shows the growth of the world's 30 largest cities between 1970 and 2010. Use the buttons on the left to toggle proportional symbols showing the population of each city in the given year and the percent population change over the preceding 5-year interval. Use the buttons on the bottom and the slider bar to play through the animation.
Click on the map

This Flash-based interactive map provided my very first computer programming experience. Disclaimer: It was done for a class, not really for the BBC. And it's way cooler than any maps that are actually on the BBC's website. Please don't sue me, Englishpeople.