1) Up (2009)
Oh, Pixar! Why would you do this to us?? This is supposed to be a childrens' movies!
In 2009, the acclaimed CGI studio raised the bar (which it had pretty much set itself) for sad kids' film scenes with the truly astonishing opening to 'Up'. A montage lasting just a few minutes, the scene charts the love story between Carl and Ellie from childhood to marriage to old age, right up to her sad death. In that short time, it somehow manages to encapsulate all the dizzying highs of human relationships, before suddenly and unexpectedly bringing the audience down to its painful, crushing lows. The fact that the characters are human rather than anthropomorphic animals makes the heartache all the more immediate. An utterly beautiful, truly heartbreaking moment of cinematic genius.