The Gothic short stories of Edgar Allan Poe are characterized by an unexpected, usually twisted, occurrence at the end. In the middle of The Fall of the House of Usher, for example, the narrator helps a school friend, Roderick Usher, entomb his twin sister Madeleine in a vault in the family home. At the end, however, not only does the supposedly dead Madeleine come back to life, her reappearance seems to bring about both the death of her brother and the literal collapse of the family home. What exactly the narrator sees in the form of Madeleine, however, is not clear. He may see a hallucination, a ghost, or a real person.
The narrator may of shared a join hallucination with Usher. The fact that both were going insane and shared a strong bond of friendship makes this possible. The narrator spent a long time trying to cheer up Usher, and his insanity might of affected him.
"We painted and read together; or I listened, as if in a dream, to the wild improvisations of his speaking guitar." Having such close contact with a mad man could of thrown the narrator over the edge. It isn't likely that the house suddenly just collapsed at the end of the story, perhaps it was all just in the man's head. "...my brain reeled as I saw the might walls rushing asunder." A reeling brain could of been the cause of the apparent collapse of the House of Usher.
It is more possible that the narrator saw a ghost or some form of reincarnation of Madeleine's spirit. After all, Madeleine was locked in the vault for at least seven days without food or water. It is hard to believe that she survived such a long period of time and even if she...