The climax of "Leiningen Versus the Ants" occurs when Leiningen, in a final effort to save himself and his men, covers himself with as much protection as he can and runs two miles through the swarm of ants to try to breach the dam, flood his plantation and drown the ants. This last desperate effort is the peak of tension in the story.
A climax is the turning point, or point of greatest intensity, in a story that leads to the conclusion. Typically, setting and characters are established in the beginning of a story. Next comes the rising action, which is a series of problems or challenges the protagonists face. This is followed by the climax.
"Leiningen Versus the Ants" follows the classic short story plot pattern. First, Leiningen is introduced as the owner of a coffee plantation in Brazil. A Brazilian official warns him that a huge, deadly swarm of ants is approaching, but unlike his neighbors, Leiningen decides to stay and fight them instead of flee. Because of Leiningen's courage, some of the plantation workers stay to help him dig canals and set petroleum fires. For days, they battle the ants. They manage to temporarily hold them off, but instead of retreating and leaving, the ants find ways to overcome their defenses and continue to advance. When it appears that they will become overwhelmed, Leiningen makes his desperate run. At the end of the story, Leiningen is badly hurt but recovering.