Last week, I posted an infographic of billionaires who got their start late in life. To balance this out, here's an infographic of the world's youngest billionaires, courtesy of the U.K.-based gambling site Lottoland.

The infographic shows their current wealth, but as far as I can tell, all of them made their first billion dollars before they turned 30.

What I find fascinating about these young moguls is that they've continued working as entrepreneurs even though they have far more money than a sane person could spend in a lifetime.

I think that says something about entrepreneurs in general. Most of us aren't in it just for money (although that's nice when it comes). We also want to do something significant and (corny as it sounds) change the world for the better.