The most sophisticated software in history was written by a team of people whose names we do not know.
It’s a computer worm. The worm was written, probably, between 2005 and 2010.
Because the worm is so complex and sophisticated, I can only give the most superficial outline of what it does.
If you've heard this story before, you already know what this worm is and the effect that it had. If you haven't, then you should ready this story. It's incredible. All the more so for being true.