I found these three Worldmapper chloropleths striking. Remember, in this sort of map country sizes change depending on the relevant measured variable – in this case, population.
First, the world’s population by country in 2002:
Next, the world population by country if you only count the children:
Finally, the world population if you only count centenarians. The U.S. balloons, as does Western Europe and Japan.
In case you’re curious, here’s the full presentation deck from which this came: