ex.) In Titanic when Rose has to let go of Jack's hand in the water. In Romeo and Juliet, when Juliet awakes to find Romeo dead.
ex.) In the movie The Ring when the little girl steps out of the tv. In Stephen King's (who is the master at this type of moment) The Shining when the wife finds the stacks of typed pages that say "All work and no play makes Jack a dull boy."
Ex.) In the Mortal Instruments series, the scene with Jace and Clary in the fairy court. In Charlaine Harris' Sookie books, (hmm, there are so many, where to start), I'll say in the fourth one Dead to the World, the shower scene with Sookie and Eric.
ex.) In Knocked Up when the friend walks into the delivery room and she screams in her most demonic voice for him to get out.
Ex.) The final dance in Dirty Dancing. The scene in Sixteen Candles where the car pulls away from the church and Molly Ringwald's character sees Jake Ryan leaning against his car waiting for her. The examples are all over the place. Every book and movie has one of these, it's the climax. But the key is to make the reader really care about getting there. We have to feel personally invested in the outcome. If not, we're left cold.