actually that was the first thing that came to my mind, what a ginormous job it must have been with a team hunkering down and working with multiple experts from around the world, for many unsung months (maybe years). However I personally believe that Google not shouting about how hard this was, explicitly, makes it all the more commendable. Quiet, amazing work, not shouted from the rooftops by PR/marketing people. Honest, modest, brilliance. Like all the best things.