This paper examines Monkey Hill, a hamadryas baboon enclosure built in the 1920s at the London Zoo. Georges Bataille’s experience staring across at the baboons during a visit in 1927 inspired writings in which the upper parts of the primate body—the mouth, the face, the pineal gland—represented humanity, and the lower parts—the ano-genital or perineal regions—symbolized a base and contemptible animality associated with the baboons. This human-animal binary is reflected in the architecture of Monkey Hill. Its large, waterless moat divided the baboons from the zoo’s human visitors, operating as a management device to maintain distance between humans and other animals. Despite efforts to distance humanity, encounters like Bataille’s reveal the fragility of the human-animal divide. The paper thus explores notions of civilization and animality and how this dichotomy is constructed and maintained.