What is the climax of Lord of the Flies?

The climax of the novel is Piggy’s death at Castle Rock, when Roger rolls a boulder that kills Piggy and shatters the conch.

This moment is the point where the boys’ fragile civilization finally collapses. Ralph, Piggy, Sam, and Eric go to Jack’s fort to demand the return of Piggy’s glasses, which Jack’s tribe has stolen to make fire. Piggy still believes in reason and moral order: he wants to appeal to Jack because “what’s right’s right,” and he carries the conch as a sign that rules and fair speech should still matter.

At Castle Rock, that belief fails completely. Jack’s tribe captures Sam and Eric, and Jack shows off his power by saying, “See? They do what I want.” Piggy then raises the conch and makes one last appeal for sense over savagery. Roger responds by pushing a boulder from above. Ralph manages to dodge it, but Piggy, nearly blind without his glasses, cannot. The boulder hits him and knocks him over the cliff, and the conch explodes.

Piggy’s death destroys two of the novel’s main symbols at once: Piggy, who stands for intelligence and rational thought, and the conch, which stands for law, order, and civilized speech. After both are destroyed, Jack screams and throws his spear at Ralph, aiming to kill. Ralph flees into the jungle, and the final chapter becomes a hunt in which Jack’s tribe tries to kill him too.

Notably, Simon’s earlier murder is also a major turning point because it proves that all the boys can be swept into violence. Piggy’s death serves as the novel's climax because it leaves Ralph alone as the last remaining figure of civilized order. From that point onward, the island belongs almost entirely to Jack and Roger, who rule using fear and force.