Where does the climax of the play "A Streetcar named Desire" occur?

To add to what the previous respondent has stated, this scene is clearly the climax of the play, but Blanche's sanity has been in question long before this. This is the final straw that finalizes her break from reality that began when her husband killed himself. His suicide was a reaction to Blanche's discovery of his homosexuality, but it also led Blanche on a path of self-doubt. She feels that the only way she can give herself worth is to be attractive to men, and she leads them on in order to bask in the glow of their affections. This does not work with Stanley. He sees through her and takes what he wants to take from her, leaving her shattered when the only illusion that she had to keep her going, her beauty and desirability, is thrust in her face.