What Is the Climax to the "Cask of Amontillado"?

"The Cask of Amontillado" by Edgar Allan Poe is a story of revenge. After an unendurable insult, Montresor leads Fortunato into his vaults, plying him with wine along the way. When they are deep in the catacombs, Montresor chains Fortunato to a wall inside a small alcove and begins sealing it off with a wall of bricks. Fortunato thinks it is a joke at first, but Montresor keeps building the wall. Finally, with only one stone left to be placed, Fortunato cries out, "For the love of God, Montresor!" Montresor replies, "Yes, for the love of God" before putting the last stone in place.