Tearjerker / Ice Age

  • Nadia using her last ounce of strength to push Roshan over to Manny in hopes that he will be saved,
  • The Art Shift Flashback in the cave that reveals Manny's Dark and Troubled Past. Even Diego has tears in his eyes at that scene.
  • Diego taking the mortal blow for Manny during the battle with Soto at the end to protect him, as it is obvious that Soto's incisors slashed him fatally, and let's not forget that blow to his head that he got. And as he dies (the commentary for the first film confirms that he actually did die in that scene) he selflessly insists that Manny and Sid forget about him, since he wants to make sure Roshan gets home as much as they do now. This scene is especially heartbreaking if you remember that Manny has only recently lost his family, and now he is losing someone close to him all over again. His brimming eyes as he watches Diego leave them only serve to drive the point home.
http://tvtropes.org/pmwiki/pmwiki.php/Tearjerker/IceAge