Mosaics are nuts. I find it fascinating that people can create large images while focusing on the seemingly insignificant little parts. Mosaics where the ingredients are individual pictures rather than colored squares or something are even nuttier.
Take this Barry Bonds rookie card poster for example. You could give me a million pieces of colored squares and have me put it together like a puzzle and I'd fail within ten minutes. But this place via here had it done with too many tiny little pictures. And Bonds came out looking like Bonds. As a Pirate fan and former baseball card collector, I'd recognize that card anywhere.
Good thing they decided to use Bonds' rookie card and not one from his last years in San Fransisco. They'd need plenty more little pictures to adequately capture the swelling of his head.