Many might remember Hans Rosling and the impressive talks he delivered at TED where he demonstrated Trendalyzer, a data visualisation software which presents information in a digestible form which can be interpreted intuitively. For those who don't, here's a YouTube clip of one of his talks where he shows the audience how to eat out of his hand.
Trendalyzer was acquired by Google and appears to have since been incorporated into its Public Data Directory. The result is a service that takes public data from organisations around the world and presents them through graphs including Hans Rosling's bubble plot. It is hours of fun!
The following is a bubble chart pitting, as a function of time, the average number of births per woman against the life expectancy of the period. Click on the play button or drag the slider at the bottom to manually increment the time value. It is simply fascinating.